JP3652687B2 - Clamping method and apparatus for injection molding machine, etc. - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a mold clamping method and apparatus for an injection molding machine or a die casting machine (hereinafter referred to as an injection molding machine or the like). In particular, in order to shorten a molding cycle, a tie bar and a movable die plate are moved during a mold closing operation. The present invention relates to a mold clamping method and apparatus for mechanical engagement.
[0002]
[Prior art]
In order to shorten the molding cycle, as a mold clamping method in which the movable die plate mechanically engages the tie bar and the movable die plate during the mold closing operation, for example, Japanese Patent Laid-Open Nos. 10-296809 (Patent Document 1) and 10 There is a method disclosed in Japanese Patent No. -296810 (Patent Document 2). In the former example, as shown in FIGS. 1 and 4 (not shown) of Japanese Patent Laid-Open No. 10-296809, a moving plate is slidably disposed with respect to a tie bar having one end fixed to the fixed plate. A clamping cylinder is formed in the vicinity of the insertion portion of the moving plate with the tie bar, and its piston member protrudes from the moving plate. Opening / closing means with a multi-partition nut that engages with the threaded part formed on the outer periphery of the tie bar is fixed to the moving plate, and the opening / closing part is driven immediately before the mold closing to engage the multi-partition nut with the threaded part. . By disposing a plurality of pairs of split nuts, the movable platen can be engaged even when the mold is closed.
[0003]
In the latter example, as shown in FIG. 1 (not shown) of Japanese Patent Laid-Open No. 10-296810, a tie bar having a ram cylinder for mold clamping in a moving plate and having one end fixed to a fixed plate is inserted. A pair of half nuts are provided on both sides of the moving board. Then, one half nut close to the fixed platen can be moved independently in the axial direction of the tie bar, and an appropriate meshing position with the tie bar is set in advance at the time of initial setting. When it comes into contact with the one half nut, the other half nut is driven and meshed. In this case, the interval between the two half nuts is configured to be maintained at an integral multiple of the thread pitch of the tie bar.
[0004]
In each of the above examples, the tie bars are all fixed to the fixed platen, but the tie bar itself is moved in the axial direction during the mold closing operation, and the engaging means is operated while the moving plate and the tie bar are both moving ( Japanese Patent Laid-Open No. 10-296739 (Patent Document 3) has been proposed. Hereinafter, a method of moving the tie bar will be described with reference to FIGS.
[0005]
6 to 9, reference numeral 10 denotes a fixed platen. A fixed mold 12 is attached to the fixed platen 10, and a moving mold 16 is attached to the fixed platen 10 via a tie bar 14. The board 18 is disposed so as to oppose and move freely.
[0006]
Further, a nut member 24 that is screwed with a feed screw shaft 22 that is coupled via a connecting member 22a from a mold opening / closing servo motor 20 as a moving means fixed to the fixed platen 10 is attached to a part of the moving platen 18. Thus, the movable plate 18 is moved forward and backward with respect to the fixed plate 10 by the rotational drive of the feed screw shaft 22, and the mold opening / closing operation of the movable die 16 with respect to the fixed die 12 is performed.
[0007]
On the other hand, on the outer surface of the moving plate 18, an engagement means is engaged with the screw portion (or groove portion) 14a formed on the distal end side of the tie bar 14 penetrating the moving plate 18 by the opening / closing cylinder 26. A half nut 28 for clamping is attached. Further, a mold clamping cylinder 30 is provided at a portion where the fixed platen 10 is connected to the tie bar 14, and a piston part 14b formed at the other end of the tie bar 14 is fitted into the mold clamping cylinder 30 so that the tie bar 14 is pivoted. Configure to move forward and backward in the direction.
[0008]
Then, a screw shaft 31 is screwed onto the shaft portion 14c (see FIG. 8) of the tie bar 14 from the piston portion 14b to the outer portion of the mold clamping cylinder 30, and is coupled to the screw shaft 31 via a connecting member 31a. Then, a tie bar sliding servo motor 32 configured to slide the tie bar 14 in the front-rear axis direction by rotating the tie bar 14 is attached. In FIG. 6, reference numeral 34 indicates a nozzle portion of an injection molding machine.
[0009]
In the composite mold clamping apparatus configured as described above, when the molds 12 and 16 are attached and the mold thickness is adjusted, as shown in FIG. 6, first, the mold closing operation is started from the mold open limit position. The engagement relationship between the tie bar 14 and the movable platen 18 by the mold clamping half nut 28 is released.
[0010]
Next, a mold closing operation is performed by the mold opening / closing servomotor 20. In this case, when the mold is closed, the open / close cylinder 26 is operated to close the half nut 28. At this time, it is convenient if the half nut 28 and the threaded portion 14a of the tie bar 14 can be properly meshed with each other. However, since the screw pitch is actually shifted, there is little meshing.
[0011]
Therefore, the tie bar slide servomotor 32 is used to slightly advance the tie bar 14 to the left, and the drive of the servo motor 32 is stopped at the position where the half nut 28 is engaged with the screw portion 14a of the tie bar 14, and the half nut 28 is engaged with the threaded portion 14a of the tie bar 14 (see FIG. 7). The position of the tie bar 14 at this time is read and stored by a position detecting means (not shown). Therefore, in the subsequent molding operation, the servomotor 32 controls the tie bar 14 so that it is always in this position at the limit of advancement of the mold by the moving board 18. In this way, the mold thickness adjustment operation is completed.
[0012]
According to this composite mold clamping apparatus, as described above, after adjusting the meshing position of the mold clamping half nut 28, the mold opening / closing servo motor 20 is driven from the state shown in FIG. The tie bar slide servomotor 32 is driven after reaching an arbitrary position (position B in FIG. 9) in the vicinity of the forward limit, and the tie bar 14 starts to move rightward. , And control the speed of 32 to synchronize the relative speed (that is, make the relative speed zero). Then, when the rightward speeds of the movable board 18 and the tie bar 14 are synchronized (position A in FIG. 9) and the relative speed at the specific position is 0, the half nut 28 is closed, and the threaded portion 14a of the tie bar 14 Engage (see FIG. 9).
[0013]
Further, according to this composite mold clamping apparatus, as described above, after adjusting the meshing position of the mold clamping half nut 28, the molding operation including the mold closing operation as shown in FIG. 9 is started.
[0014]
First, the mold opening / closing servomotor 20 is driven from the state shown in FIG. 6 to move the moving board 18 forward (rightward), and an arbitrary position near the mold closing limit of the moving board 18 (position B in FIG. 9). ), The tie bar 14 that has been moved to the left from the previously stored position is driven to the right by driving the tie bar sliding servo motor 32, and the speeds of the servo motors 20 and 32 are controlled respectively. The relative speed between the moving board 18 and the tie bar 14 is calculated and synchronized (that is, the relative speed is set to 0). Then, when the rightward speeds of the movable board 18 and the tie bar 14 are synchronized at a predetermined position (position A in FIG. 9), the meshing between the half nut 28 and the threaded portion 14a of the tie bar 14 is detected.
[0015]
If in the proper meshing position, the half nut 28 is closed and meshed with the threaded portion 14a of the tie bar 14 while maintaining speed control so that the relative speed becomes zero. When the meshing is completed and the movable platen 18 reaches the mold closing limit, the position of the tie bar 14 is read by a position detector (not shown) and compared with the position of the tie bar 14 stored at the time of the above-described mold thickness adjustment. If the comparison results match, the mold clamping and boosting operation are started.
[0016]
If it is not an appropriate meshing position, the speed of one of the servo motors 20 and 32 is controlled. In FIG. 9, the tie bar slide servo motor 32 is controlled to accelerate and decelerate as indicated by the dotted line with respect to the synchronous speed. When the proper meshing position is reached (position C in FIG. 9), the speed is returned to the synchronous speed again, and the half nut 28 is closed while maintaining the speed control so that the relative speed becomes zero. 14 screw portions 14a are engaged with each other.
[0017]
Furthermore, by making the spiral groove or the square groove of the half nut 28 meshing with the threaded portion 14a of the tie bar 14 wider than the meshing position, it is more wide with respect to the corresponding mountain of the threaded portion 14a of the tie bar 14. By providing the gap, the half nut 28 can be closed smoothly.
[0018]
Next, pressure oil is introduced into the mold clamping chamber side 30 a of the mold clamping cylinder 30 to generate a high-pressure mold clamping force via the tie bar 14. After setting in this way, the molded product is manufactured through the injection, filling, holding and cooling processes of the molten resin material to the mold through the nozzle part 34 of the injection molding machine, and the process proceeds to the mold opening process. .
[0019]
In this mold opening process, pressure oil is introduced into the return side 30b (the high pressure mold opening chamber side) of the mold clamping cylinder 30, and the moving plate 18 is screwed with the feed screw shaft 22 via the nut member 24. The mold opening can be performed by driving the mold opening / closing servomotor 20 in reverse. At the same time, the engagement of the mold clamping half nut 28 with the tie bar 14 is released during the mold opening operation. At the same time, the tie bar slide servo motor 32 is reversely driven to move the tie bar 14 leftward to the position B in FIG.
[0020]
In this way, the one-cycle operation of injection molding can be completed. Accordingly, in the composite mold clamping apparatus shown in FIGS. 6 to 9, the mold clamping half nut 28 can be opened and closed during mold opening and closing, and the molding cycle time can be shortened.
[0021]
Although the prior art described in the above three publications has been exemplified, in any of the techniques, at the time of initial setting, that is, when the mold is newly replaced, the mold clamping half nut is located at a specific position of the outer peripheral thread portion of the tie bar. Must be set to engage, and the position must be mechanically and electrically held and memorized.
[0022]
In the example disclosed in Japanese Patent Application Laid-Open No. 10-296809, the engaging means moves relative to the tie bar integrally with the moving plate. Although the engaging means is engaged during this movement, in order to suppress the shock at the time of engagement, it is necessary to slow down the moving speed after all even though it has a plurality of pairs of half nuts. There is a difficulty that it takes.
[0023]
In addition, in the example disclosed in Japanese Patent Laid-Open No. 10-296810, a pair of mold clamping half nuts are arranged to engage with both sides of the moving board, in addition to the structural complexity, There is a difficulty in that driving means for moving one half nut independently must be arranged separately.
[0024]
Further, the example described in FIGS. 6 to 9 is a system in which the half nut is engaged with the half nut 28 and the tie bar 14 while the relative speed between the half nut 28 and the tie bar 14 is zero during the movement of the movable platen 18. The tie bar 14 and the tie bar 14 need to be positioned relative to each other during the movement, and the drive control of both the moving board and the tie bar is complicated. Further, as shown in FIG. 8, a tie bar sliding servo motor 32 is attached to the end of the mold clamping cylinder 30 and the tie bar is operated at different timings of the mold closing operation and the mold clamping operation in the axial direction of the tie bar 14. There is a problem that two driving means are required for the movement of the motor.
[0025]
[Patent Document 1]
Japanese Patent Laid-Open No. 10-296809 (all items, all figures)
[Patent Document 2]
JP-A-10-296810 (all items, all figures)
[Patent Document 3]
Japanese Patent Laid-Open No. 10-296739 (all items, all drawings)
[0026]
As a result of earnestly examining the above-mentioned problems of the prior art, the inventors of the present application do not make the relative speed between the tie bar and the moving board zero, but rather use the speed difference to control the driving timing of the engaging means. It has been found that the above problems can be solved.
[0027]
[Problems to be solved by the invention]
Accordingly, it is an object of the present invention to provide a mold clamping method and apparatus for a novel injection molding machine and the like that realizes shortening of a molding cycle without requiring an operation for initially setting an engagement position on a tie bar. .
[0028]
[Means for Solving the Problems]
A mold clamping method according to the present invention for solving the above-mentioned problems is as follows.
A fixed die plate having a fixed die attached thereto, a moving die plate having a movable die attached and fixed thereto and disposed opposite to the fixed die plate, and one end portion supported on the fixed die plate side, the moving die A plurality of tie bars that slideably support the plate toward the fixed die plate; a first driving means for opening and closing the mold that moves the moving die plate toward and away from the fixed die plate; And a second driving means for pressing the moving die plate toward the fixed die plate after the fixed mold and the moving mold are brought into contact with each other by the driving means; and the plurality of tie bars are moved to the moving die plate. A third drive means that moves relative to the axial direction relative to the movable die plate, and an engagement portion that is attached to the movable die plate and formed on the outer periphery of the plurality of tie bars Engaging means for coupling, in the mold clamping process such as injection molding machine having a mold clamping mechanism having,
During the mold closing operation of the movable die plate toward the fixed die plate by the first driving means, the plurality of tie bars are moved at a moving speed different from the moving speed of the moving die plate by the third driving means. Thus, the movement in the mold closing direction is started, and the engagement means is driven in a state in which the relative speed between the movable die plate and the plurality of tie bars reaches a predetermined value to move the plurality of tie bars and the movable die plate. After the mechanical coupling, the second driving means is driven to perform a mold clamping operation.
[0029]
Furthermore, an apparatus according to the present invention for solving the above-described problems is
A fixed die plate with a fixed die attached thereto, a movable die plate with a movable die attached and fixed thereto and disposed opposite to the fixed die plate, and one end portion supported on the fixed die plate side and the movable die plate A plurality of tie bars that slidably support toward the fixed die plate, a first driving means for opening and closing the mold that moves the moving die plate toward and away from the fixed die plate, and the first drive A second driving means for pressing the movable die plate toward the fixed die plate after the fixed mold and the movable mold are in contact with each other; and the plurality of tie bars on the movable die plate And a third driving means for relatively moving in the axial direction, and an engagement formed on the outer periphery of the plurality of tie bars attached to the movable die plate. And a mold clamping mechanism having an engagement means coupled with the injection, and a mold clamping control device for controlling each drive of the first drive means, the second drive means, the third drive means and the engagement means In mold clamping devices such as molding machines,
During the mold closing operation, the mold clamping control device instructs the first drive means to move at a low speed to switch the moving speed of the moving die plate to a low speed before the mold closing is completed, and at the same time with the low speed movement command. Thereafter, a first command unit that commands the third driving means to move the plurality of tie bars at a speed different from a low speed movement speed of the moving die plate, and the moving die plate and the plurality of tie bars Detection means for detecting relative speed, a setting unit for presetting a value of the relative speed with which the engagement means can be engaged, and the engagement means when the output of the detection means reaches the set value And a second command unit that commands to drive the motor.
[0030]
In that case, the second driving means can be configured to also serve as the third driving means.
[0031]
Further, in this case, the second driving means that also serves as the third driving means is configured to form a cylinder portion for mold clamping at a portion that supports one end of the plurality of tie bars on the fixed die plate side. A piston slidable in the cylinder may be provided at the end of the tie bar.
[0032]
The second driving means is constituted by a clamping cylinder formed in the movable die plate, and the third driving means is a screw formed on a fixed die plate side support portion on the outer periphery of the plurality of tie bars. And a plurality of nuts that are screwed together with the threaded portions to restrict axial movement and are housed in a fixed die plate, and a plurality of drive motors that rotationally drive the nuts. it can.
[0033]
[Action]
During the mold closing operation with the movable die plate facing the fixed die plate by the first driving means, the tie bar is moved in the mold closing direction by the third driving means, and the engagement is performed with the relative speed reaching within a predetermined value. After the tie bar and the movable die plate are mechanically coupled by driving the means, the second driving means is driven to perform the mold clamping operation.
[0034]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, examples based on the embodiment of the present invention will be described in detail with reference to FIGS. 1 to 5.
[0035]
FIG. 1 shows a schematic cross section of a main part of a mold clamping mechanism in an injection molding machine or the like according to the present invention. In FIG. 1, reference numeral 50 denotes a fixed die plate, and a fixed mold 52 is attached and fixed to the left side surface thereof. On the other hand, a moving die plate 56 having a moving mold 54 attached and fixed to the right side surface thereof is disposed opposite to the fixed die plate 50.
[0036]
Reference numeral 68 denotes a tie bar, the right end of which is supported by the fixed die plate 50 and the left end of the tie bar is inserted through the moving die plate 56. In an injection molding machine or the like, normally, four tie bars 68 are arranged at each corner portion of the fixed die plate 50 and the movable die plate 56, but the function of each tie bar is the same for the purpose of the present invention. Is represented by a single tie bar 68. In FIG. 1, upper portions of the fixed die plate 50 and the movable die plate 56 are omitted.
[0037]
Reference numeral 78 is a die opening / closing drive feed screw for moving the movable die plate 56 forward and backward with respect to the fixed die plate 50, and its right end portion is rotatably supported by a bearing portion 81 attached to the fixed die plate 50. The rotary shaft of the AC servo motor 74 attached and fixed to the right side surface of the fixed die plate 50 is connected via a ring 82. Reference numeral 76 is a rotary encoder.
[0038]
The left side of the feed screw 78 is screwed with a nut 80 attached to the movable die plate 56. Accordingly, the movable die plate 56 is slidably guided by the tie bar 68 by driving the AC servo motor 74. The fixed die plate 50 can be advanced and retracted. Further, the moving amount and moving direction of the moving die plate 56 are always detected by the encoder 76 and given to the mold clamping control device shown in FIG. 2 to be used for position control of the moving die plate 56. Reference numeral 62 is a mold clamping cylinder formed in the fixed die plate 50, and its right end surface is constituted by a lid 58.
[0039]
A piston 66 of a clamping cylinder 62 is attached to the right end portion of the tie bar 68, and a detection rod 64 for position detection fixed to the piston 66 is disposed through the lid 58. Reference numeral 60 is a tie bar position sensor for detecting the position of the magnetic detection rod 64 when it moves integrally with the piston 66, that is, the position of the tie bar 68. These detection rod 64 and tie bar position sensor 60 are position detectors for the tie bar 68. Is configured.
[0040]
A screw portion 70 is formed on the outer periphery of the left portion of the tie bar 68, and the screw portion 70 is provided in a pair of known engagement means 72 that is fixedly attached to the left side surface of the movable die plate 56. Is engaged with the split nut 73. The split nut 73 and the threaded portion 70 constitute an engaging portion of the present invention. Details of the supply and discharge of pressure oil to the mold clamping cylinder 62 and the engaging means 72 are omitted. Although the engaging means 72 is described as a hydraulic system, the split nut 73 can be advanced and retracted to and from the threaded portion 70 using an electric motor.
[0041]
As described above, the main part of the mold clamping mechanism to which the present invention is applied has been described with reference to FIG. 1, but the point is that the mold clamping operation is performed while the moving die plate 56 is moving rightward in FIG. The cylinder 62 is driven to move the tie bar 68 in the same direction, and the engagement means 72 is driven to complete the engagement. The mold thickness adjustment operation at the initial setting, that is, the mold is once closed. The conventional operation of engaging the engaging portion with the engaging means 72 can be omitted.
[0042]
FIG. 2 shows, as a control block diagram, a mold clamping control device for controlling the mold clamping mechanism shown in FIG. In FIG. 2, reference numeral 100 denotes an arithmetic processing unit for controlling the mold clamping operation. The arithmetic processing unit 100 is identical to the central arithmetic processing unit CPU and the bus BUS connected to the central arithmetic processing unit CPU. It is composed of a data memory DM, a program memory PM, and an interface unit iF that exchanges signals with external input / output devices connected to the bus BUS. The interface unit iF includes A / D conversion and D / A conversion functions required for signal exchange.
[0043]
Reference numerals 60 and 76 denote the tie bar position sensor and the encoder described with reference to FIG. 1, and each provide an input signal to the arithmetic processing unit 100. On the other hand, as output signals from the arithmetic processing unit 100, the split nut control valve 72A for driving and controlling the engagement means 72, the mold clamping cylinder control valve 62A for driving and controlling the mold clamping cylinder 62, and the AC servomotor 74 are driven and controlled. A servo driver 74A is provided. A signal from the encoder 76 to the servo driver 74A is used for feedback control of the AC servo motor 74.
[0044]
The program memory PM in the arithmetic processing unit 100 is provided with a memory area 101 for storing a mold clamping control program comprising a series of commands given to the central processing unit CPU for performing a mold clamping operation.
[0045]
Further, in the data memory DM in the arithmetic processing unit 100, the difference between the moving speeds of the moving die plate 56 and the tie bar 68 during the mold closing operation, that is, the allowable setting value a of the relative speed is stored in the memory area 102 in advance. . In the data memory DM, for example, the current position and speed of the tie bar 68, the current position and speed of the moving die plate 56, the moving speed command value of the moving die plate 56, and the switching position or time for switching the moving speed from high speed to low speed, Various data memory areas necessary for driving and controlling the mold clamping mechanism, such as the position or time at which the tie bar 68 starts to move, its command moving speed, and the engagement completion time of the engagement means 72, are provided. Details are omitted.
[0046]
FIG. 3 is a flowchart showing the contents of the mold clamping control program stored in the memory area 101 in the program memory PM, and FIG. 4 shows the movement die plate 56, tie bar 68 and engaging means 72 during the mold closing operation. A speed diagram of each of the split nuts 73 is shown. Hereinafter, the process of the mold clamping operation will be described along each step of the flowchart of FIG. 3 with reference to FIG. 1, FIG. 2, and FIG. For convenience of description in the flowchart, the letters MD and TB are used for the movable die plate and tie bar, respectively.
[0047]
Now, when a mold closing command is given from an overall control device (not shown) such as an injection molding machine, the mold clamping control program is started (START).
In step ST1, the moving die plate 56 is instructed to move forward, that is, to move at a high speed toward the fixed die plate 50 at a preset speed. In step ST2, it is determined whether or not the movable die plate 56 has reached the low speed switching position (corresponding to time t1 in FIG. 4). If the determination result is negative in step ST2 (indicated by N and the same applies hereinafter), the high-speed movement in step ST1 is continuously commanded.
[0048]
If the determination result is affirmative (indicated by Y and the same applies hereinafter), a low-speed movement of the moving die plate 56 is commanded in step ST3. Subsequently, at step ST4, if the driving start position or time of the tie bar 68 is set to be the same as the low speed switching time t1 of the moving die plate 56, the low speed movement of the tie bar 68 is commanded (the mold clamping cylinder of FIG. 2). Drive command to the control valve 62A).
[0049]
Next, in step ST5, it is instructed to calculate the difference between the moving speed of the moving die plate 56 and the tie bar 68, that is, the relative speed from the current moving speed. The current moving speeds are obtained by differentiating the position signals from the tie bar position sensor 60 and the encoder 76 in FIG. In step ST6, it is determined whether or not the relative speed has become equal to or less than the set value a in the area 102 of the data memory DM. When the determination result is N, steps ST3 to ST6 are continued. When the determination result in step ST6 is Y, the process proceeds to step ST7, where a command is given to drive the split nut 73 forward toward the threaded portion 70 of the tie bar 68 (drive command to the split nut control valve 74A in FIG. 2). The command movement speed of the tie bar 68 is set to a speed having a predetermined difference smaller than the set value a with respect to the command low speed movement speed S1 of the moving die plate 56, as indicated by S2 in FIG.
[0050]
In step ST8, it is determined whether or not the engagement is completed. When the determination result is N, in step ST9, after waiting for a certain time T1, step ST8 is executed again. When the determination result is Y in step ST8 (corresponding to time t3 in FIG. 4), the process proceeds to step ST10, and it is determined in step ST10 whether the movable die plate 56 has reached the mold closing position. When the determination result is N, in step ST11, after waiting for a certain time T2, step ST10 is executed again. When the determination result is Y (time t4 in FIG. 4), the process proceeds to step ST12 to instruct the driving of the moving die plate 56 and the tie bar 68 to be stopped.
[0051]
Next, in step ST <b> 13, an instruction is given to supply pressure oil to the left chamber side of the mold clamping cylinder 62 to perform mold clamping. Further, in step ST14, it is determined whether or not the mold clamping is completed, and when the determination result is N, after waiting for a certain time T3, step ST14 is executed again. When the determination result is Y, the mold clamping operation ends (END), and the completion of the mold clamping operation is notified to the entire control device (not shown).
[0052]
Although not shown in the flowchart of FIG. 3, since the tie bar 68 is forcibly moved at a low speed integrally with the moving die plate 56 after the engagement completion time t3 when the determination result is Y in step ST8. As shown in FIG. 4, the speed S2 of the tie bar 68 becomes the speed S1 after time t3. At that time, the clamping cylinder control valve 62A is commanded so that the supply and discharge of the pressure oil to the clamping cylinder 62 is adjusted so that the tie bar 68 does not resist the low-speed movement of the moving die plate 56.
[0053]
In FIG. 4, the driving start time of the tie bar 68 is the same as the low speed switching time t1 of the moving die plate 56, but may be delayed from the time t1, for example, during the deceleration of the moving die plate 56. In FIG. 4, the time (t 3 -t 2) required from the start of the split nut 73 to the completion of engagement depends on the relative speed and the phase state at the time t 2 between the split nut 73 and the threaded portion 70 of the tie bar 68. Therefore, the time (t3-t2) can be monitored and the speed of the moving die plate 56 or tie bar 68 can be changed within the allowable speed difference a to shorten the time. In addition, if the phase state is almost one pitch as a result of the initial monitoring, the mold clamping control is performed so that the driving start time of the tie bar 68 is delayed by a predetermined time in the next mold closing operation in consideration of the speed difference and the pitch amount. It is also possible to modify the program.
[0054]
FIG. 5 shows another mold clamping mechanism to which the present invention is applied.
[0055]
In FIG. 5, reference numerals 50, 52, 54, and 68 are components corresponding to the reference numerals in FIG. The main points different from the mold clamping mechanism of FIG. 1 are that the mold clamping cylinder is provided on the movable die plate side instead of the fixed die plate side, and a fixed die for moving the tie bar 68 in the axial direction during the mold closing operation. A nut 88 that engages with a screw portion 68A formed on the right outer periphery of the tie bar 68 in the plate 50 is arranged to allow only its rotation, and an electric servomotor 90 to which an encoder 91 is attached is used to transmit the transmission gear 89 and the nut 88 outer peripheral gear. The nut 88 is rotationally driven through the portion. As in the case of FIG. 1, the rotation of the tie bar 68 is restricted by a key or the like although not shown.
[0056]
In FIG. 5, the moving die plate includes two parts, that is, a first supporting member 56A in which a moving mold 54 is attached and fixed, and one end side of a ram 86 is fixed on the opposite side to the moving mold, and the other ram. A tie bar 68 is slidably inserted into both the members 56A and 56B. The second support member 56B is formed with a clamping cylinder 95 that houses a thick-diameter portion as a piston.
[0057]
Reference numerals 92 and 94 denote a split nut and a drive cylinder, which are engaged with the threaded portion 68B in the same manner as the engaging means 72 in FIG. Reference numeral 84 denotes a cylinder for opening and closing the mold, and the piston rod tip is fixed to a support 56C below the first support member 56A. In the mold clamping mechanism of FIG. 1, the mold clamping cylinder 62 performs the movement of the tie bar 68 during the mold closing operation and the original mold clamping operation after the mold closing operation is completed. No. 95 is not used as described above.
[0058]
As mentioned above, although the Example based on the preferred embodiment of this invention was described, this invention is not limited to the said Example, Many changes are possible in the range which does not deviate from the mind of this invention. For example, the mold clamping mechanism of FIG. 1 is applied to a die casting machine, a pair of split nuts as engagement means is constituted by three or more split nuts, and the split nut advance / retract drive means is provided with a position detector. It is composed of a servo motor, the outer peripheral part of the tie bar of the engaging part is formed in a rack shape instead of a screw, and the groove width of the rack or screw part is made larger than the peak part of the split nut, or the groove is inclined. Design modifications such as providing engagement to facilitate engagement are applications of the present invention.
[0059]
【The invention's effect】
A mold clamping method for an injection molding machine or the like according to the present invention is as follows.
During the mold closing operation with the moving die plate directed toward the fixed die plate by the first driving means, the plurality of tie bars are moved in the mold closing direction by the third driving means, and the relative relationship between the moving die plate and the plurality of tie bars is determined. When the speed reaches a predetermined value, the engagement means is driven to mechanically couple the plurality of tie bars and the movable die plate, and in the coupled state, the movable die plate is further moved toward the fixed die plate. Since the mold clamping method is used in which the second driving means is driven after the fixed mold and the movable mold are brought into contact with each other, the initial setting such as mold thickness adjustment as in the prior art is required. In addition, it becomes possible to complete the engagement by driving the engaging means by utilizing the difference in moving speed between the moving die plate and the plurality of tie bars during the mold closing operation, and as a result, the time of the molding cycle can be reduced. An effect that can be reduced in the width.
[0060]
Further, the mold clamping device according to the present invention includes:
A fixed die plate to which a fixed mold is fixed and a movable die are mounted and fixed, and a movable die plate and one end portion of the fixed die plate that are arranged opposite to the fixed die plate are supported on the fixed die plate side, and the movable die plate is The plurality of tie bars that are slidably supported toward the fixed die plate and the movable die plate are moved forward and backward toward the fixed die plate, and the first driving means for opening and closing the mold and the first driving means are used to fix the tie bar. A second driving means for clamping the moving die plate toward the fixed die plate after the mold and the moving mold contact each other, and the plurality of tie bars relative to the moving die plate Third driving means for moving in the axial direction and an engagement portion attached to the movable die plate and formed on the outer periphery of the plurality of tie bars. And an injection molding machine provided with a mold clamping control device that controls each drive of the first drive means, the second drive means, the third drive means, and the engagement means. A mold clamping device such as
During the mold closing operation, the mold clamping control device instructs the first drive means to move at a low speed to switch the moving speed of the moving die plate to a low speed before the mold closing is completed, and at the same time with the low speed movement command. Thereafter, a first command unit that commands the third drive unit to move the plurality of tie bars, a detection unit that detects a relative speed between the movable die plate and the plurality of tie bars, and the engagement unit A setting unit that presets the value of the relative speed that can be engaged, and a second command unit that commands the engagement unit to be driven when the output of the detection unit reaches the set value. In addition, the second driving means also serves as the third driving means by utilizing the fact that the second driving means and the third driving means operate at different times in the mold clamping operation process. Configure to Since, in addition to the effect of the clamping method, the structure of the mold clamping mechanism can be simplified than the conventional, there is an effect that can be inexpensively configured in cost.
[Brief description of the drawings]
FIG. 1 is a diagram showing a main part of an embodiment of a mold clamping mechanism in an injection molding machine or the like according to the present invention.
FIG. 2 is a block diagram of a mold clamping control device that controls the operation of a mold clamping mechanism in an injection molding machine or the like according to the present invention.
FIG. 3 is a flowchart showing a mold clamping control program for controlling the operation of a mold clamping mechanism in an injection molding machine or the like according to the present invention.
4 is a graph for explaining the operation during the mold closing operation of the movable die plate, the tie bar and the split nut shown in FIG. 1;
FIG. 5 is a view showing a main part of another embodiment of a mold clamping mechanism in an injection molding machine or the like according to the present invention.
FIG. 6 is a schematic sectional view showing a main part of a mold clamping mechanism in a conventional injection molding machine or the like.
7 is a schematic cross-sectional view showing an operation state when the mold thickness adjustment of the mold clamping mechanism shown in FIG. 6 is completed. FIG.
8 is an enlarged cross-sectional view of a main part showing a main part configuration of a mold clamping cylinder of the mold clamping mechanism shown in FIG. 6;
9 is an explanatory view showing an operating state during a mold closing operation in the mold clamping mechanism shown in FIG. 6;
[Explanation of symbols]
50 fixed die plate
52 Fixed mold
54 Moving mold
56 Moving die plate
56A First support member
56B Second support member
56C support
58 lid
60 Tie bar position sensor
62 Clamping cylinder
62A Clamping cylinder control valve
64 detection rod
66 piston
68 Tie Bar
68A Screw part
68B Screw part
70 Screw part
72 engaging means
72A Split nut control valve
73 Split nut
74 AC servo motor
74A servo driver
76 Encoder
78 Lead screw
80 nuts
81 Bearing part
82 coupling
84 cylinders
86 Lamb
88 nuts
89 Transmission gear
90 Electric servo motor
91 Encoder
92 split nut
94 Drive cylinder
95 Clamping cylinder
100 arithmetic processing unit
101 Memory area
102 Memory area
DM data memory
PM program memory

Claims (11)

A fixed die plate having a fixed die attached thereto, a moving die plate having a movable die attached and fixed thereto and disposed opposite to the fixed die plate, and one end portion supported on the fixed die plate side, the moving die A plurality of tie bars that slideably support the plate toward the fixed die plate; a first driving means for opening and closing the mold that moves the moving die plate toward and away from the fixed die plate; And a second driving means for pressing the moving die plate toward the fixed die plate after the fixed mold and the moving mold are brought into contact with each other by the driving means; and the plurality of tie bars are moved to the moving die plate. A third drive means that moves relative to the axial direction relative to the movable die plate, and an engagement portion that is attached to the movable die plate and formed on the outer periphery of the plurality of tie bars Engaging means for coupling, in the mold clamping process such as injection molding machine having a mold clamping mechanism having,
During the mold closing operation of the movable die plate toward the fixed die plate by the first driving means, the plurality of tie bars are moved at a moving speed different from the moving speed of the moving die plate by the third driving means. Thus, the movement in the mold closing direction is started, and the engagement means is driven in a state in which the relative speed between the movable die plate and the plurality of tie bars reaches a predetermined value to move the plurality of tie bars and the movable die plate. A mold-clamping method for an injection molding machine or the like, wherein the mold-clamping operation is performed by driving the second driving means after mechanically coupling. 2. The mold clamping method for an injection molding machine or the like according to claim 1, wherein when the moving speed of the movable die plate is switched to a low speed before completion of mold closing, the movement of the tie bar is started simultaneously or during deceleration. 3. The moving speed of one or both of the first and second driving means according to claim 1 or 2, wherein when the engagement is not completed after a predetermined time has elapsed after a driving command to the engaging means is given. A mold clamping method for an injection molding machine or the like, characterized in that the pressure is changed. 3. The movement start timing of the plurality of tie bars in the next mold closing operation based on an elapsed time from when a drive command to the engagement means is given until engagement is completed. A mold clamping method for an injection molding machine or the like, characterized in that it is changed. A fixed die plate with a fixed die attached thereto, a movable die plate with a movable die attached and fixed thereto and disposed opposite to the fixed die plate, and one end portion supported on the fixed die plate side and the movable die plate A plurality of tie bars that slidably support toward the fixed die plate, a first driving means for opening and closing the mold that moves the moving die plate toward and away from the fixed die plate, and the first drive A second driving means for pressing the movable die plate toward the fixed die plate after the fixed mold and the movable mold are in contact with each other; and the plurality of tie bars on the movable die plate And a third driving means for relatively moving in the axial direction, and an engagement formed on the outer periphery of the plurality of tie bars attached to the movable die plate. And a mold clamping mechanism having an engagement means coupled with the injection, and a mold clamping control device for controlling each drive of the first drive means, the second drive means, the third drive means and the engagement means In mold clamping devices such as molding machines,
During the mold closing operation, the mold clamping control device instructs the first drive means to move at a low speed to switch the moving speed of the moving die plate to a low speed before the mold closing is completed, and at the same time with the low speed movement command. Thereafter, a first command unit that commands the third driving means to move the plurality of tie bars at a speed different from a low speed movement speed of the moving die plate, and the moving die plate and the plurality of tie bars Detection means for detecting relative speed, a setting unit for presetting a value of the relative speed with which the engagement means can be engaged, and the engagement means when the output of the detection means reaches the set value A mold clamping device for an injection molding machine or the like, comprising: a second command unit that commands to drive the motor. 6. A mold clamping apparatus for an injection molding machine or the like according to claim 5, wherein the second drive means includes a mold clamping mechanism configured to also serve as the third drive means. 7. The second drive means that also serves as the third drive means according to claim 6, wherein a plurality of mold clamping cylinders are formed on a portion that supports one end of the plurality of tie bars on the fixed die plate side. A mold clamping device for an injection molding machine or the like, characterized in that a piston slidable in the cylinder is provided at the end of the tie bar. 6. The method according to claim 5, wherein the second driving means is constituted by a clamping cylinder formed in the movable die plate, and the third driving means is provided on a fixed die plate side support portion on the outer periphery of the plurality of tie bars. And a plurality of nuts that are screwed to the threaded portions and controlled to move in the axial direction and accommodated in a fixed die plate, and a plurality of drive motors that rotationally drive the nuts. A mold clamping device such as an injection molding machine. 9. The electric motor according to claim 5, wherein the first driving means is an electric servo motor attached to the fixed die plate, and a screw shaft coupled to a rotating shaft of the electric servo motor and extending to the movable die plate side. A mold clamping apparatus for an injection molding machine or the like, comprising a nut attached to a movable die plate and screwed into the screw shaft. 6. The mold clamping apparatus according to claim 5, wherein the engagement means includes a pair of split nuts and a drive means for moving the same pair of split nuts back and forth in the engagement portion. 11. The mold clamping apparatus for an injection molding machine or the like according to claim 10, wherein the engaging means is composed of a plurality of split nuts.

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