JP2017077626A - Mold clamping abnormality determination method of toggle type mold clamping mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mold clamping abnormality determination method of a toggle type mold clamping mechanism, which can readily determine occurrence of an inverse toggle state and can prevent a lock-up state from occurring.SOLUTION: An abnormality determination method of a toggle type mold clamping mechanism 10 for performing mold closing, mold clamping and mold opening of a movable plate 15 by bending and stretching a toggle link relative to stationary plate 14 is achieved by a mold clamping abnormality determination method of a toggle type mold clamping mechanism in which during mold closing, mold clamping and mold opening, a movement strain amount of a plurality of tie bars 17 that guide the movable plate 15 in the mold closing and opening direction is measured by a tie bar movement strain amount detection means, a clamping force calculated from the movement strain amount is supervised, and when the mold clamping force 1 at least in one of an initial and final stage of the mold clamping state is larger than a permissible value 1 of the mold clamping force 2 in a middle stage of the mold clamping state, the mold clamping abnormality is determined.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a mold clamping abnormality determination method for a toggle type mold clamping mechanism used in a die casting machine, an injection molding machine or the like.

  In die casting machines and injection molding machines, these two molds are clamped by a mold clamping mechanism that closes, clamps, and opens the movable mold attached to the movable plate relative to the fixed die attached to the fixed platen. The mold is opened and closed, and a mold clamping force is applied to the closed mold. After the light metal or resin in the molten state is injected and filled into the mold cavity (space) formed inside the mold closed by the injection mechanism, the light metal or resin in the mold cavity is cooled and solidified. By opening these two molds, a molded product having a desired shape can be obtained.

  Such a mold clamping mechanism is roughly classified into a direct pressure type mold clamping mechanism and a toggle type mold clamping mechanism. The latter toggle type mold clamping mechanism is a mold clamping mechanism that bends and extends a toggle link to perform mold closing, mold clamping, and mold opening of the movable mold. Toggle links that can be used with (linear actuators), obtain the desired mold clamping force with a drive source with a smaller driving force (boost characteristics), and obtain the maximum mold clamping force In the fully extended state (locking state), there is an advantage such that the output of the driving source is not required to be maintained.

  A general toggle type mold clamping mechanism 10 will be described with reference to FIG. The toggle type mold clamping mechanism 10 of FIG. 1 is a hydraulic drive type. A fixed platen 14 is fixedly placed on the machine base 13 via a fixed key 14a. The movable platen 15 is slidably mounted on the machine base 13. A mold 12 including a fixed mold 12a and a movable mold 12b is attached between the fixed plate 14 and the movable plate 15, and the movable plate 15 is moved in the front-rear direction (mold opening / closing direction / left-right direction in FIG. 1). Thereby, the movable mold 12b can be opened and closed with respect to the fixed mold 12a.

  A toggle link is mounted behind the movable platen 15 (left side in FIG. 1). One end of the toggle link 22 is connected to the upper side of the movable platen 15 via a toggle pin 40, and one end of the mid link 23 is connected to the other end. The other end of the mid link 23 is connected to the upper side of the link housing 16 via a toggle pin, and a substantially middle portion of the mid link 23 is also connected to one end of the cross head link 24 via a toggle pin. The other end of the cross head link 24 is connected to the upper side of the cross head 25. On the other hand, a toggle link similar to the above is configured between the movable platen 15 and the lower side of the link housing 16, and the other end of the lower crosshead link 24 is connected to the lower side of the crosshead 25. The end (on the right side in FIG. 1) of the cylinder rod 21 of the mold clamping cylinder 20 (linear actuator) fixed to the link housing 16 is coupled to the cross head 25. In addition, although all the toggle pins shall be shown with the code | symbol 40, in FIG. 1, only the toggle pin 40 of the one end side (movable board 15 side) of the toggle link 22 is described typically. In addition, the toggle link 22, the mid link 23, and the crosshead link 24 may be collectively referred to as a toggle link.

Four tie bars 17 pass through the fixed platen 14, the movable platen 15 and the link housing 16, and each tie bar 17 is screwed to the fixed platen 14 by a fixing nut 18, and the link housing 16 by a movable nut 19. It is fixed to the screw.
Similarly to the movable platen 15, the link housing 16 is also slidably mounted on the machine base 13. Here, the movable nut 19 can be rotated by a die height adjusting device (not shown) arranged on the same surface as the movable nut 19 of the link housing 16. With this configuration, the movable nut 19 is rotated by the die height adjusting device, and the link housing 16 and the movable platen 15 connected to the link housing 16 by a toggle link according to the mold thickness of the mold 12 and a desired mold clamping force, The position in the mold opening / closing direction on the machine base 13 can be adjusted.

  High pressure hydraulic oil is supplied to the mold clamping cylinder 20 from a hydraulic device (not shown), and the cylinder rod 21 is moved forward (right side in FIG. 1) (operating oil is supplied to the head chamber 20a) or retracted (FIG. 1). Left side) (operating oil is supplied to the rod chamber 20b). By this operation, the cross head 25 can be moved in the mold opening / closing direction, and the toggle plate can be bent and extended to move the movable platen 15 in the mold opening / closing direction.

  FIG. 2 shows a state in which the movable platen 15 is moved backward (left side in FIG. 2), and the movable die 12b is opened from the fixed die 12a. The hydraulic oil is supplied to the rod chamber 20b of the mold clamping cylinder 20, the cylinder rod 21 is retracted, and the movable link 15 is retracted by bending the toggle link. In this mold open state, the molded product molded in the mold 12 is removed from the mold by an unillustrated take-out means and conveyed outside the machine. In this state, the toggle link 22 and the mid link 23 are in the maximum bent state, and the distance between the fixed nut 18 and the movable nut 19 is L.

  From the state of FIG. 2, when hydraulic oil is supplied to the head chamber 20a of the clamping cylinder 20 and the cylinder rod 21 is advanced (right side in FIG. 2), the toggle link is extended and the movable platen 15 is advanced. it can. Then, as shown in FIG. 1, the movable mold 12b is brought into contact (mold touch) with the fixed mold 12a. In this state, the toggle link 22 and the mid link 23 are bent, and the distance between the fixed nut 18 and the movable nut 19 is L.

  If the cylinder rod 21 is further moved forward (right side in FIG. 1) from this state, the cross head 25 is also moved forward, and the toggle link 22 and the mid link 23 are aligned in a straight line (fixing nut 18 and The distance between the movable nuts 19 is L + α (alpha)), and a mold clamping force is applied to the mold 12. As described above, the state shown in FIG. 1 (the toggle link 22 and the mid link 23 are bent) is changed to the state shown in FIG. 3 (the toggle link 22 and the mid link 23 are in a straight line). The tie bar 17 fixed to the housing 16 can be extended (elastically deformed) by a length α, and as a reaction force, a mold clamping force according to the extension amount of the tie bar 17 can be applied to the mold 12. It should be noted that during the transition from the state of FIG. 1 to the state of FIG. 3, each of the four tie bars 17 is stretched uniformly and a desired stretch amount (desired mold clamping force) can be obtained. The position of the link housing 16 on the machine base 13 in the mold opening / closing direction is adjusted in advance by rotating the movable nut 19.

  In such a toggle type mold clamping mechanism, the ratio (toggle magnification) of the pressing force with which the movable platen 15 presses the mold 12 with respect to the driving force of the mold clamping cylinder 20 varies depending on the position of the cross head 25. Specifically, the cross head 25 is moved to the fixed platen 14 side, the bent state of the toggle link 22 and the mid link 23 is shifted to the extended state, and the toggle magnification increases as both the links approach a straight line. . That is, in the mold clamping state in which both links are in a straight line, the pressing force with which the movable plate 15 presses the mold 12 can be maximized with respect to the driving force of the mold clamping cylinder 20. A mold clamping force larger than the driving force can be generated with respect to the driving force (a boost characteristic).

  FIG. 4 shows a normal mold clamping operation. In the middle of the mold clamping shown in FIG. 4A (when the mold clamping force is increasing), the toggle link 22 and the mid link 23 are extended until they are aligned by moving the cross head 25 forward (right side in FIG. 4). . At this time, a compressive force indicated by an arrow acts on the toggle link 22, the mid link 23, and the cross head link 24 from the toggle pins at both ends of each link. Then, when the clamping is completed as shown in FIG. 4B in which the toggle link 22 and the mid link 23 are aligned, the compression force acting from the toggle pins at both ends of each of the toggle link 22 and the mid link 23 is maximum. On the other hand, the cross head link 24 is in a state where the compressive force or tensile force from the toggle pins at both ends thereof does not act. Therefore, as described above, in order to maintain this state (locking state), it is not necessary to continue supplying hydraulic oil to the head chamber 20a of the mold clamping cylinder 20 and maintain the output to the mold clamping cylinder 20. .

  FIG. 5 shows a toggle pin 40 and a bush 40 a that connect the link housing 16 and the mid link 24. The toggle pin 40 is fixed to the link housing 16 side by a toggle pin cover (not shown), and the bush 40a is fitted and fixed to the mid link 24. In the bending / extending operation of the toggle link at the time of opening and closing the mold, the mid link 24 rotates around the toggle pin 40 as a rotation center. At that time, since lubricating oil is supplied between the toggle pin 40 and the bush 40a, it can rotate smoothly even when a large mold clamping force is applied.

  However, if the lubrication oil supply is inappropriate, or even if the lubrication oil supply is appropriate, the bending / extending operation of the toggle link at the time of mold opening / closing is rotational sliding of each link with a load. Therefore, the progress of wear of the bushes combined with all the link pins 40 cannot be avoided due to long-term use. For example, with respect to the toggle pin 40 and the bush 40a that connect the link housing 16 and the mid link 24, as shown in FIG. 5, the toggle pin 40 of the bush 40a is bitten into the fixed plate 14 side (the right side in FIG. 5) of the bush 40a. Wear (a worn portion in FIG. 5) proceeds. As a result, in the bending / extending operation of the toggle link at the time of opening and closing the mold, the rotary motion of each toggle link is fluctuated and the relative positional relationship between the movable platen 15 and the link housing 16 is also affected.

  FIG. 6 shows a state when the toggle type mold clamping mechanism 10 shifts from the mold clamping state to the mold opening process. FIG. 6A shows a case where a normal mold clamping state where the toggle link 22 and the mid link 23 are in a straight line shifts to a mold opening process. Since the wear of the bush 40a combined with the toggle pin 40 of each link is not progressing and accurate rotation sliding without backlash of each link is ensured, the toggle link 22 and the mid link 23 on the upper side, Both the side toggle link 22 and the mid link 23 start to bend inward symmetrically to the center line side as the crosshead 25 moves backward (left side in FIG. 6), and a smooth mold opening process can be performed.

  However, when wear of the bush 40a progresses and rattling occurs in the rotation and sliding of each link, the toggle link 22 and the mid link 23 do not become a straight line even in the mold-clamped state, as shown in FIG. The upper side and lower side toggle links 22 and the mid links 23 are bent so as to slightly protrude downward due to their own weights. Further, due to the bent state of the upper and lower links protruding downward, the cross head 25 is pressed downward by the same weight from the upper cross head link 24, and the same weight from the lower cross head link 24, Under the downward tensile force, the crosshead 25 as a whole receives a downward load.

  On the other hand, parallel to the cylinder rod 21 of the mold clamping cylinder 20, guide rods (not shown) that are horizontally supported from the link housing 16 side are arranged on the left and right sides of the cylinder rod 21 (the back and front of the drawing in FIG. 6). . The cross head 25 is also guided and supported by the guide rod in the mold opening / closing direction via a guide rod bush (not shown). Therefore, in the state where the guide rod bush is not worn, the movement in the mold opening / closing direction is supported with respect to the downward load as described above. It slides downward from the horizontal position at, or the backlash occurs and tilts.

  Further, regarding the cylinder rod 21 of the mold clamping cylinder 20, a piston (not shown) on the head chamber 20 a side of the rod within the body of the mold clamping cylinder 20, and the cross head 25 of the mold clamping cylinder 20 of the rod. In a state where the side sliding portion (not shown) is separated by a predetermined distance, two points are supported horizontally. Therefore, even if a downward load is applied to the cross head 25 that is coupled to the end of the cylinder rod 21 on the movable platen 15 side (the right side in FIG. 6), the above two-point support distance is secured by a predetermined distance. In this state, the cylinder rod 21 can be supported horizontally. However, in the mold clamping state, the cylinder rod 21 of the mold clamping cylinder 20 is in the state in which the rod is most advanced (right side in FIG. 6), so the distance of the two-point support becomes the shortest, and the crosshead 25 is It is difficult to support the downward load acting on the tip of the cylinder rod 21 via the intermediate rod 21. Therefore, as the wear of the toggle pin bush 40a and the wear of the guide rod bush progress, the cross head 25 that receives a downward load from both the upper and lower cross head links 24 has a clamped state in an inclined posture. To do.

  Such a state of the lower toggle link in a state where the crosshead 25 is tilted and both the upper and lower toggle links are bent downward at the time of mold clamping is referred to as a reverse toggle state. When such a reverse toggle state (P portion in FIG. 6B) occurs, the mold opening process is performed by retracting the crosshead 25 (left side in FIG. 6) depending on the degree of the reverse toggle state. Even so, since the lower toggle link 22 and the mid link 23 are already bent downward, these two links can be bent toward the center line side of the toggle type mold clamping mechanism 10 (upward in FIG. 6). It becomes difficult. This is called a lock-up state.

  In addition, when the reverse toggle state occurs in the lower toggle link in this way, the upper toggle link 22 and the mid link 23 are in a mold-clamping state just before the straight line is bent, and the lower toggle link 22 The link 22 and the mid link 23 are in a mold-clamping state by bending once further from a state where the link 22 and the mid link 23 are bent upward and then further downwardly bending. Therefore, in the state shown in FIG. 6B, the upper and lower tie bars 17 are not extended to the extension amount α of the tie bar 17 necessary for generating the set mold clamping force, and are extended as described later. The expansion is limited to the amount α ″ and the extension amount β (beta) (α ″ <α, β <α), and it is difficult to open the mold. It is also difficult to give.

  Further, when the mold clamping cylinder 20 is hydraulic, the cylinder rod 21 of the mold clamping cylinder 20 is retracted (left side in FIG. 6) during the mold opening operation, that is, the rod chamber 20b side whose pressure receiving area is smaller than the head chamber 20a. In general, the hydraulic oil is supplied to the cylinder rod 21 so that the retraction force of the cylinder rod 21 is smaller than the advance force of the cylinder rod 21 during the mold clamping operation. As a result, it is difficult to eliminate this lock-up state when the mold is opened from the mold-clamping state even if a lock-up state is generated when the toggle link is extended from the mold closed state to the mold-clamped state. There are many cases. When the lock-up state occurs, it is necessary to immediately stop the casting operation and repair the mold clamping device.

  As described above, since the weight of the toggle link 22 and the mid link 23 acts downward, the reverse toggle state mainly due to the progress of wear of the toggle pin bush and the guide rod bush is the downward toggle link. Often occurs. However, in the reverse toggle state, the height of the movable platen 15 guided by the tie bar 17 and moved in the mold opening / closing direction with respect to the machine base 13 and the movable platen 15 (the metal plate of the movable platen 15) are fixed. This also occurs when the parallelism of the mold mounting surface is not properly adjusted. In such a case, on the contrary, the upper and lower toggle links are bent upward, and the upper toggle link is reversely toggled or the bushes are worn down. May be in a reverse toggle state. In addition, when adjustment of the height of the movable platen 15 or the parallelism of the movable platen 15 with respect to the fixed platen 14 is not appropriate, the wear of the toggle pin bush and the guide rod bushing is advanced faster than normal, In some cases, the reverse toggle state may occur due to a combination of inappropriate adjustment of the movable platen 15 and the progress of wear of the bushes, such as causing a wear state. In other words, the reverse toggle state occurs when the geometrical symmetry of the toggle link is not ensured within the allowable range, and any reverse toggle state occurs regardless of the cause of the reverse toggle state. In this case, it becomes a lock-up state, making it difficult to open the mold.

  In order to prevent the occurrence of the reverse toggle state of the toggle type mold clamping mechanism and the occurrence of the lock-up state due to the occurrence of the reverse toggle state, the applicant has disclosed Patent Document 1 (Toggle type clamp device in the toggle type mold clamping device). A mechanism deterioration diagnosis method and apparatus) have been devised. Specifically, the relative positional relationship of each component constituting the toggle type mold clamping mechanism is measured by a non-contact type displacement sensor, and deterioration is diagnosed by a difference from a reference value.

JP 2011-005796 A

  In Patent Document 1, as the relative positional relationship between the components constituting the toggle type mold clamping mechanism, the inclination of the cross head and the distance between the movable platen and the link housing are listed. Since these relative positional relationships are measured with a non-contact type displacement sensor, it is not necessary to place sensors directly on each movable component for each mold opening / closing operation, and there are restrictions on sensor mounting positions and wiring routing. Therefore, it is easy to measure the reverse toggle state of the lower toggle link and its degree in the mold clamping state.

  However, since the toggle type clamping mechanism of a die casting machine or an injection molding machine is a mechanism composed of a plurality of constituent members, the inclination of the cross head, which is a constituent member, and the distance between the movable platen and the link housing can be adjusted. Causes slight mechanical errors and machine differences. By making these mechanical errors and machine differences within an allowable range, the quality of the toggle type mold clamping mechanism is maintained, but in the toggle mechanism degradation diagnosis method and apparatus in the toggle type mold clamping apparatus of Patent Document 1, The inclination of these cross heads and the distance between the movable platen and the link housing are measured, and the deterioration is diagnosed by comparing the measured value with a preset reference value (allowable value). In other words, there is a mechanical error and machine difference in the normal normal crosshead tilt and the distance between the movable platen and the link housing within the allowable range. Even in the tightening mechanism, there is a problem that the reference value for performing the deterioration diagnosis cannot be set uniformly.

  In addition, because there are mechanical errors and machine differences for each mechanism as described above, even if the inclination of the crosshead that becomes the reverse toggle state and the distance between the movable platen and the link housing are obtained by calculation on the desk, These measured values that are actually in a reverse toggle state may differ from the calculations on the desk. Therefore, in order to set the reference value (allowable value) for actually diagnosing (determining) the reverse toggle state in combination with the above-described points where the measurement values serving as the reference in the normal state are not uniform, Since the operation record of the toggle type mold clamping mechanism and the record data of these measured values when the lock-up state occurs during the operation record are necessary, a suitable reference value (allowable value) is required until these data are accumulated. ) Is difficult to set.

  The present invention has been made in view of the above-described problems. Specifically, a toggle type mold that can easily determine the occurrence of a reverse toggle state and prevent the occurrence of a lockup state. It is an object of the present invention to provide a mold clamping abnormality determination method for a clamping mechanism.

The above object of the present invention is a toggle type mold in which a movable mold attached to a movable plate is closed / clamped / opened by bending / extending a toggle link with respect to the fixed die attached to the fixed plate. A method of determining a clamping abnormality of a clamping mechanism,
A dynamic strain amount of a plurality of tie bars that guide the movable plate in the mold opening / closing direction during the mold closing, the mold clamping, and the mold opening is measured by a tie bar dynamic strain amount detecting means and calculated from the dynamic strain amount. While monitoring the clamping force to be
Toggle type mold clamping mechanism for determining that the mold clamping is abnormal when the mold clamping force 1 in at least one of the initial stage and the final stage of the mold clamping state is larger than the allowable value 1 than the mold clamping force 2 in the middle stage of the mold clamping state. This is achieved by the mold clamping abnormality determination method.

And, in this mold type clamping mechanism mold clamping abnormality detection method, an alarm is issued at the time of the first mold clamping abnormality judgment,
It is preferable not to start the next cycle if the difference between the mold clamping force 1 and the mold clamping force 2 is larger than the allowable value 2 at the second or later mold clamping abnormality determination.

Further, the above object of the present invention is to toggle the movable mold attached to the movable platen to the fixed die attached to the fixed platen by bending and extending the toggle link, closing the mold, clamping and opening the die. A mold clamping abnormality determination method for a type mold clamping mechanism,
During the mold closing, mold clamping, and mold opening, the dynamic strain amount of a plurality of tie bars that guide the movable plate in the mold opening / closing direction is measured by the tie bar dynamic strain amount detecting means, and the dynamic strain amount is monitored. As well as
Toggle type mold clamping mechanism for determining that the mold clamping is abnormal when the dynamic strain amount 1 in at least one of the initial and final stages of the mold clamping state is larger than the allowable value 1 than the dynamic strain quantity 2 in the middle period of the mold clamping state. This is also achieved by the mold clamping abnormality determination method.

And also in this mold type clamping mechanism mold clamping abnormality detection method, when the first mold clamping abnormality determination, an alarm is transmitted,
It is preferable not to start the next cycle when the difference between the dynamic strain amount 1 and the dynamic strain amount 2 is larger than the allowable value 2 at the second and subsequent mold clamping abnormality determination.

  Further, in any of the above-described methods for detecting a mold clamping abnormality of the toggle type mold clamping mechanism, when the mold clamping abnormality is in the mold clamping state, the toggle link exceeds the extended state, and the reverse of the normal bending direction. It is assumed that a bending state occurs.

According to the present invention, a mold clamping abnormality detection method for a toggle type mold clamping mechanism is configured such that a movable mold attached to a movable plate is bent and extended with respect to a fixed die attached to a fixed plate, A method for determining a mold clamping abnormality of a toggle type mold clamping mechanism for closing, mold clamping and mold opening,
A dynamic strain amount of a plurality of tie bars that guide the movable plate in the mold opening / closing direction during the mold closing, the mold clamping, and the mold opening is measured by a tie bar dynamic strain amount detecting means and calculated from the dynamic strain amount. While monitoring the clamping force to be
In order to determine that the mold clamping is abnormal when the mold clamping force 1 in at least one of the initial and final stages of the mold clamping state is larger than the allowable value 1 than the mold clamping force 2 in the middle period of the mold clamping state, Generation | occurrence | production can be determined easily and generation | occurrence | production of a lockup state can be prevented.

Further, according to the present invention, the mold clamping abnormality detection method of the toggle type mold clamping mechanism, instead of the mold clamping force calculated from the dynamic strain amounts of a plurality of tie bars,
In order to determine that the mold clamping is abnormal when the dynamic strain amount 1 in at least one of the initial and final stages of the mold clamping state is larger than the allowable value 1 than the dynamic strain amount 2 in the middle period of the mold clamping state, Generation | occurrence | production can be determined easily and generation | occurrence | production of a lockup state can be prevented.

It is a figure which shows the general hydraulic drive toggle type clamping mechanism used for a die-casting machine or an injection molding machine. It is a figure which shows the state which opened the metal mold | die of the toggle type mold clamping mechanism. It is a figure which shows the state which is giving the mold clamping force to a metal mold | die of a toggle type mold clamping mechanism. It is a figure which shows the normal toggle mold clamping state in a toggle type mold clamping mechanism. It is a figure which shows the state with which the bush of a toggle type mold clamping mechanism is worn out. It is a figure which shows the time of a mold opening start from the mold clamping state which the normal mold clamping state and the reverse toggle state generate | occur | produced of the toggle type mold clamping mechanism. In a toggle type mold clamping mechanism, it is a figure (graph) which shows increase / decrease in mold clamping force accompanying time passage between mold closing, mold clamping, and mold opening.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the accompanying drawings.

  With reference to FIG. 7, a method for determining a clamping abnormality of a toggle type clamping mechanism according to the first embodiment of the present invention will be described. In order to perform the mold clamping abnormality determination method for the toggle mold clamping mechanism according to the first embodiment, the general toggle mold clamping mechanism 10 described with reference to FIG. . The necessary configuration is only a tie bar dynamic strain amount measuring means capable of measuring the tie bar dynamic strain amount (extension amount) in real time.

  Various tie bar dynamic strain measuring means are commercially available, but tie bar gauges and linear gauges (linear scales) are common.

  First, a tie bar gauge is one in which a strain gauge affixed to a base part is crimped to the surface of a tie bar 17 with a metal belt or the like through a protective cover such as a film and the base, and a measured value is received separately. It can be transmitted by wire or wireless to a machine or PC. A strain gauge used for a tie bar gauge is generally an isotropic conductor in which metal conductors are arranged in a comb shape on a thin insulator, and is energized in a state where the conductor is pressed against a measurement target. When stress is applied to the object to be measured during energization and it is deformed (strain is generated), the metal conductor arranged in a comb-tooth shape in the strain gauge is also deformed in the same way as the non-measuring object. The rate changes, and the current value and voltage value also change. By measuring this, the amount of deformation in one direction of the object to be measured (the amount of expansion of the tie bar 17) can be measured.

  In a simple manner, when adjusting the clamping force of the toggle type clamping mechanism 10 before shipment, a single strain gauge is adjusted to a desired strain direction (the amount of extension of the tie bar 17), and a plurality of instantaneous adhesives are used. Each tie bar 17 is attached to the same position, and the amount of extension for each tie bar 17 at the time of mold clamping is measured, and in the mold clamping state, adjustment is made so that all tie bars 17 extend substantially evenly within an allowable range (specifically Specifically, it is used for adjusting the position of the movable nut 19 with respect to each tie bar 17). On the other hand, a tie bar gauge is used when it is desired to constantly monitor the clamping force including during casting.

  In addition, a linear gauge (linear scale) may be employed when the extension amount of the tie bar 17 is to be constantly monitored. The linear gauge is a rod-shaped precision length measuring device that uses a digital scale that uses light or magnetism for the dimension detection portion, and detects and counts light pulses or magnetic pulses with a digital counter. For example, a hole in the axial direction in which a digital scale of a linear gauge to be mounted can be inserted into the end face of the tie bar 17 protruding to the fixed platen 14 side, and one end of the linear gauge is fixed to the end face side. Is fixed to the bottom of the machined hole. The end face of the tie bar 17 to which one end of the linear gauge is fixed is not affected by the extension amount of the tie bar 17 even in the mold clamping state or the injection filling process. Therefore, when the tie bar 17 is extended, the position of the other end of the linear gauge fixed to the bottom of the processed hole is also moved in the extension direction (axial direction) of the tie bar 17, so that the entire linear gauge is inserted. The length extension can be measured directly and accurately.

  Linear gauges are more expensive than strain gauges and tie bar gauges, and have disadvantages such as the need for drilling at the end of tie bar 17, while sensors and electrical wiring are not exposed on the outer peripheral surface of tie bar 17. Since it is hard to be influenced by the environment, it is more suitable for the case where the sensor is permanently attached.

  The tie bar dynamic strain measurement means is not only a tie bar gauge or linear gauge, but also a distance sensor that can accurately measure the distance between two points using various light beams such as laser and infrared rays and ultrasonic waves. It may be arranged in the vicinity of each tie bar 17 of the fixed platen 14 and the movable platen 15, and the distance between the fixed platen 14 and the movable platen 15 is measured in real time, and the change in the distance between the platen is used as the extension amount of each tie bar 17. May be. Furthermore, the same measurement can be performed by measuring the distance between the fixed mold 14 and the movable mold 15 with various distance sensors arranged so as to face the mold side surfaces of the fixed mold 14 and the movable mold 15. . What kind of means or sensor is adopted as the tie bar dynamic strain amount measuring means may be appropriately selected.

  Here, if there is information such as the Young's modulus and diameter of the tie bar 17 of the toggle type mold clamping mechanism 10, the tie bar 17 generated as a reaction force from the amount of dynamic strain in the axial direction of the tie bar, that is, the extension amount of the tie bar 17. The calculation of each mold clamping force can be easily performed in a control device of a die casting machine or an injection molding machine having the toggle type mold clamping mechanism 10. That is, the dynamic strain amount of the tie bar 17 and the mold clamping force corresponding to the dynamic strain amount are in a one-to-one relationship, and both values have the same meaning. In the first embodiment, the dynamic strain amount of the plurality of tie bars 17 is measured in real time by the tie bar dynamic strain amount measuring means, and the mold clamping force is calculated from the dynamic strain amount. Force shall be monitored in real time. In order to simplify the drawing, the tie bar dynamic strain amount measuring means is not shown in addition to FIG.

  FIG. 7 is a diagram (graph) showing an increase / decrease in mold clamping force generated in one tie bar 17 as time elapses between mold closing, mold clamping, and mold opening in the toggle type mold clamping mechanism 10. The lower left of the graph is the origin, the horizontal axis indicates time (sec.), And the vertical axis indicates the mold clamping force (%) with the set mold clamping force being 100%. FIG. 7 (a) shows that the geometrical symmetry of the toggle link is ensured within an allowable range, and the toggle pin bush and guide rod bush are not worn, and the adjacent toggle link FIG. 5 shows increase / decrease in mold clamping force with time when normal mold closing, mold clamping, and mold opening are performed without causing a reverse toggle state.

  Until the movable mold 12b is closed to the fixed mold 12a and brought into contact (mold touch) (mold closing step A), the tie bar 17 is not expanded and no mold clamping force is generated (the mold clamping force is 0). %). 1 and 4A, the toggle link 22 and the mid link 23 are in a bent state, and the distance between the fixed nut 18 and the movable nut 19 is L.

  If the cylinder rod 21 is further moved forward (right side in FIG. 1) from this state, the cross head 25 is also moved forward, and the toggle link 22 and the mid link 23 are aligned in a straight line (fixing nut 18 and The distance between the movable nuts 19 is L + α (alpha)), and the mold clamping force is applied to the mold 12. During the transition to the mold clamping state, as shown in FIG. 7A, a mold clamping force is generated and reaches a set mold clamping force (clamping force 100%) all at once (mold clamping force applying step B). ). As described above, when the toggle link 22 and the mid link 23 are made straight, no compression force or tensile force is applied to the cross head link 24 from the toggle pins at both ends, and the output needs to be maintained in the clamping cylinder 20. There is no.

  After a preset clamping time (clamping process C) has elapsed, as shown in FIG. 2, the movable rod 15 is retracted by retracting the cylinder rod 21 of the clamping cylinder 20 and bending the toggle link. Let During this time, the mold clamping force is released as the set mold clamping force (the mold clamping force 100%) is reduced to 0% at once (the mold clamping force releasing step D), and the movable platen 15 continues to move backward. (Mold opening process E). In this embodiment, the mold clamping force applying process B, the mold clamping process C, and the mold clamping force releasing process D in FIG. 7 are collectively referred to as “mold clamping”. It shall be called "state".

  As described above, the graph of the increase / decrease of the clamping force with the passage of time when normal mold closing, mold clamping, and mold opening is performed is the mold clamping continuous to the mold clamping force applying process B for any tie bar. The mold clamping force (mold clamping force 1) in the initial stage of the state and the final stage of the mold clamping state that continues to the mold clamping force release process D is substantially the same as the mold clamping force (mold clamping force 2) in the middle period of the mold clamping state. As a result, the graph in this case has a substantially trapezoidal shape, and the relationship of mold clamping force 1≈mold clamping force 2≈set mold clamping force is established.

  On the other hand, due to the progress of wear of the toggle pin bush and guide rod bush and the adjustment of the height and parallelism of the movable platen 15, the geometrical vertical symmetry of the toggle link is not ensured within an allowable range. When the reverse toggle state occurs in either the lower or upper toggle link, the tie bar 17 in the vicinity where the reverse toggle state has occurred is shown in the Q part of FIG. 7B in the initial and final stages of the mold clamping state. Furthermore, a phenomenon occurs in which a mold clamping force (clamping force 1) exceeding a medium-term mold clamping force (mold clamping force 2) is generated for a short time. This is a phenomenon that does not exist in the graph of FIG. 7A in which normal mold closing, mold clamping, and mold opening are performed. As shown in FIG. 7, the time elapses between mold closing, mold clamping, and mold opening. In the graph showing the increase or decrease of the accompanying mold clamping force, it appears as a clear difference in the shape of the graph, so that visual confirmation is easy. In this graph shown in FIG. 7 (b), the toggle link 22 and the mid link 23 in which the reverse toggle state has occurred have a slight protrusion amount (bending angle) opposite to the normal bending direction. It is assumed that mold closing and mold opening are performed in the same manner as closing and mold opening.

  The phenomenon shown in the Q part in FIG. 7B is assumed to occur for the following reason. In the toggle type mold clamping device 10, the toggle link 22 and the mid link 23 as shown in FIG. 3 are in a straight line with the cylinder rod 21 of the mold clamping cylinder 20 advanced to the mechanical advance limit of the cylinder. The design / clamping force adjustment is performed so that the tie bar 17 is in a locked state in which the tie bar 17 is extended by a length (for example, α) corresponding to the set clamping force. Therefore, when the geometrical symmetry of the toggle link is not ensured within an allowable range due to the progress of wear of the toggle pin bush and the guide rod bush, the cylinder rod 21 of the clamping cylinder 20 Prior to reaching the forward limit position, the toggle link in which the reverse toggle state occurs is in a locking state as shown in FIG. 3 (initial stage of the mold clamping state).

  Since the wear of the toggle pin bush proceeds in the mold opening and closing direction, the distance between the fixed nut 18 and the movable nut 19 in this locking state before the cylinder rod 21 of the mold clamping cylinder 20 reaches its forward limit position is L + α ′. (Α ′ <α). When the cylinder rod 21 of the mold clamping cylinder 20 reaches this position (assuming a virtual locking state), the maximum mold clamping force (mold clamping force 1) in this state is generated, and then the cylinder rod 21 is moved to the machine. Since the toggle link 22 and the mid link 23 are only shifted from the virtual locking state to the reverse toggle state during the forward advance to the forward limit (the initial state of the mold clamping state), the mold clamping force (tie bar extension amount) increases. When the cylinder rod 21 reaches the mechanical advance limit (a reverse toggle state occurs), the distance between the fixed nut 18 and the movable nut 19 is L + α ″ (α "<Α '), and the mold clamping force (clamping force 2) corresponding to the tie bar extension (α") is applied and maintained (mid-stage of the mold clamping state). Tie bar extension of alpha ") is smaller than the set mold clamping force (tie bar extension of alpha) mold clamping force 1 than (tie bar extension of alpha '). Therefore, at the initial stage of the mold clamping state, the mold clamping force 1 in the virtual locking state is generated as a peak value (Q1) larger than the mold clamping force 2 in the middle period of the mold clamping state.

  Then, after the preset clamping time has elapsed, as shown in FIG. 2, the movable rod 15 is retracted by retracting the cylinder rod 21 of the clamping cylinder 20 and bending the toggle link (mold clamping). End of state). Also at this time, since the toggle link 22 and the mid link 23 are bent from the reverse toggle state via the virtual locking state, the mold clamping force 1 in the virtual locking state is applied in the middle stage of the mold clamping state. It occurs as a peak value (Q2) larger than the mold clamping force 2 at.

  Next, the wear of the toggle pin bush and the guide rod bush has not progressed, and the geometrical vertical symmetry of the toggle link is within an allowable range due to the adjustment of the height and parallelism of the movable platen 15. In this case, since the wear of the bushes has not progressed, the fixing nut 18 in the virtual locking state before the cylinder rod 21 of the mold clamping cylinder 20 reaches its forward limit position will be described. The distance between the movable nuts 19 is approximately L + α, and the maximum mold clamping force (mold clamping force 1≈set mold clamping force) in this state is generated as a peak value (Q1). Thereafter, while the cylinder rod 21 advances to the mechanical advance limit (the initial state of the mold clamping state), the toggle link 22 and the mid link 23 are merely shifted from the virtual locking state to the reverse toggle state. When the cylinder rod 21 reaches the mechanical advance limit (reverse toggle state), as shown in FIG. 6B, the tie bar extension amount) decreases without increasing, and between the fixed nut 18 and the movable nut 19. The distance is L + β (β <α), and a mold clamping force (clamping force 2) corresponding to this tie bar extension amount (β) is applied and maintained (mid-stage of the mold clamping state).

  Even in the final stage of the mold clamping state, the toggle link 22 and the mid link 23 are bent from the reverse toggle state via the virtual locking state. Therefore, the mold clamping force 1 in the virtual locking state (≈ setting type) at the final stage of the mold clamping state. (Clamping force) occurs as a peak value (Q2) larger than the mold clamping force 2 in the middle period of the mold clamping state. In the case where the reverse toggle state occurs due to a complex factor of improper adjustment relating to the movable platen 15 and the progress of wear of the bushes, the case caused by the progress of wear of the bushes is applied. Thus, regardless of the cause of the reverse toggle state, the occurrence of the reverse toggle state causes at least one of the mold clamping forces 1 in the initial and final stages of the mold clamping state to be larger than the mold clamping force 2 in the middle period of the mold clamping state. That is, the peak values in the initial and final stages of the clamping state occur.

  Note that a plurality of toggle pin bushes and guide rod bushes of the toggle link are arranged not only in the vertical direction but also in the horizontal direction, and it is unlikely that the wear of all the bushes proceeds in a perfectly balanced manner. In addition, it is difficult to consider the case where the adjustment of the movable platen 15 is not properly adjusted only for the height or the parallelism only two-dimensionally (left and right direction and vertical direction). In many cases, the height adjustment of the left and right is not appropriate, or the movable platen 15 is not properly adjusted in three dimensions with respect to the fixed platen 14 (both in the left and right direction and the vertical direction). Therefore, this peak value can occur only in one of the initial and final stages of the clamping state, depending on the degree of deviation from the tolerance of the geometrical symmetry of the toggle link. According to the applicant's experience, it often occurs only at the end of the clamping state.

  As in Patent Document 1, as the relative positional relationship of each component constituting the toggle type mold clamping mechanism, the inclination of the cross head and the distance between the movable platen and the link housing are measured, and this is used as a reference value ( In the method in which the deterioration diagnosis is performed in comparison with the allowable value), even if the reverse toggle state (temporary locking state) of the toggle link occurs, the inclination of the crosshead, the movable platen, the link housing, It is possible to diagnose (determine) the occurrence of a reverse toggle state at a stage where the difference between the distance from the reference value is small, the bending is opposite to the normal bending direction, and the amount of protrusion (bending angle) is slight. difficult.

  As described above, when the reverse toggle state occurs, the mold clamping force 2 in the middle period of the mold clamping state is lower than the set mold clamping force or the mold clamping force 1. Therefore, if only the mold clamping force 2 generated in the middle stage of the mold clamping state is monitored without monitoring the mold clamping force in real time during the mold closing, mold clamping and mold opening, it is compared with the set mold clamping force. Therefore, it is not impossible to determine the occurrence of such a reverse toggle state. However, the measured value of the mold clamping force may cause an error due to the inclusion of foreign matter between the molds. As explained above, depending on the cause of the reverse toggle state, the mold clamping force Since 1 may be substantially the same as the set mold clamping force or may be smaller than the set mold clamping force, it is difficult to make a determination based on the difference between the mold clamping force 2 and the set mold clamping force. In addition, in order to determine how much difference the reverse toggle state occurs, in the same manner as in Patent Document 1, the operation results of the toggle type mold clamping mechanism and the mold when the lockup state occurs during the operation results are obtained. Recording data of measured values such as the difference between the clamping force 2 and the set clamping force 1 or the clamping force 1 is required.

  On the other hand, in the mold clamping abnormality determination method of the toggle type mold clamping apparatus according to the present embodiment, the mold clamping force during mold closing, mold clamping and mold opening is monitored in real time, and the result is shown in FIG. As shown in the graph, the increase / decrease of the clamping force with the passage of time can be displayed in a graph, so that the occurrence of the toggle link reverse toggle state is determined by at least one clamping force 1 in the initial and final stages of the clamping state. The visual confirmation is easy as the appearance of a difference in the shape of the graph, which is larger than the middle mold clamping force 2 in the mold clamping state, that is, the occurrence of peak values in the initial and final stages of the mold clamping state.

  Naturally, when the toggle link reverse toggle state occurs, the lock-up state is reached when the difference between the mold clamping force 1 in the initial and final stage of the mold clamping state and the mold clamping force 2 in the middle period of the mold clamping state becomes large. It is difficult to determine whether it occurs. However, in the mold clamping abnormality determination method for the toggle mold clamping device according to the present embodiment, the operation results of the toggle mold clamping mechanism, and the mold clamping force 2 and the mold when the lock-up state occurs during the operation results. Even when there is no recorded data of measurement values such as the difference from the tightening force 1, the toggle link is bent in the opposite direction of the normal bending direction, and the toggle link protrusion amount (bending angle) is in a reverse toggle state. However, at least the occurrence of such a reverse toggle state itself can be easily determined visually as the appearance of a difference in graph shape. In this embodiment, the occurrence of such a reverse toggle state is referred to as a mold clamping abnormality.

  Therefore, if the mold clamping force 1 in at least one of the initial and final stages of the mold clamping state for determining the occurrence of the reverse toggle state, that is, the mold clamping abnormality, is greater than the mold clamping force 2 in the middle period of the mold clamping state. The allowable value 1 regarding the difference for determination is set to be small in advance. In addition, it is preferable to first issue an alarm when determining the first mold clamping abnormality. By this warning, an operator (operator) of a die casting machine or an injection molding machine equipped with a toggle type mold clamping mechanism can grasp that a reverse toggle state has started to occur in the toggle type mold clamping mechanism.

  Here, as shown in the graph of FIG. 7B, just because the reverse toggle state occurs, the lockup state does not occur immediately. In the lock-up state, the protrusion amount (bending angle) of the toggle link in the reverse toggle state gradually increases due to the progress of wear of the toggle pin bush and the guide rod bush and the inappropriate adjustment of the height and parallelism of the movable platen 15. Occurs when a certain limit is exceeded. Therefore, it is more preferable not to start the next cycle when the difference between the mold clamping force 1 and the mold clamping force 2 is larger than the allowable value 2 at the second and subsequent mold clamping abnormality determination. A safer option is also possible, with tolerance 2 set to approximately the same value as tolerance 1 and a cycle stop of the die-casting machine or injection molding machine equipped with a toggle type mold clamping mechanism at the time of the second abnormality determination. It is.

  However, there is no or insufficient recording data of measurement values such as the operation results of the toggle type mold clamping mechanism and the difference between the mold clamping force 2 and the mold clamping force 1 when the lockup state occurs during the operation results. In the meantime, it is preferable to set the allowable value 2 slightly larger than the allowable value 1 so that the lock-up state does not occur. In this case, after the first abnormality determination, the die casting machine or the injection molding machine including the toggle type mold clamping mechanism 10 is stopped in the next cycle when the abnormality determination is performed at an early stage after the second time. At that time, the toggle link is extended, and the degree of wear of the link pin bush and the guide rod bush is confirmed visually or by a predetermined method. Depending on the result, it may be determined to replace these bushings, or to reset the allowable value 2 a little larger and continue the operation of the die casting machine or the injection molding machine. By doing this, while preventing the occurrence of an unexpected lockup state and grasping the occurrence of the reverse toggle state, the die casting machine and the injection molding machine can be used until the appropriate replacement timing of the link pin bush and the guide rod bush. Driving can be continued.

  The embodiment described above can be applied to both the hydraulic drive type and the electric drive type as long as the toggle type mold clamping mechanism 10 is used. Further, any die-casting machine or injection molding machine provided with the toggle type mold clamping mechanism 10 can be applied.

  The present invention is not limited to the above embodiment and can be implemented in various forms. For example, in this embodiment, the dynamic strain amount of the plurality of tie bars 17 is measured in real time by the tie bar dynamic strain amount measuring means, and the mold clamping force is calculated from the dynamic strain amount. Although the clamping force is monitored in real time, as described above, the dynamic strain amount of the tie bar 17 and the mold clamping force corresponding to the dynamic strain amount have a one-to-one relationship, and both values are equivalent. It has implications.

  Therefore, even if the mold clamping force described in the present embodiment is replaced with a dynamic strain amount, the occurrence of the reverse toggle state of the toggle link is caused by the fact that at least one of the initial and final dynamic strain amounts in the mold clamping state is the mold clamping. Since it is easier to visually confirm the appearance of a difference in the shape of the graph that is larger than the medium-term dynamic strain amount 2 in the state, that is, the occurrence of peak values in the initial and final stages of the clamping state, it is the same as in this example. The effect of can be produced.

DESCRIPTION OF SYMBOLS 10 Toggle type clamping mechanism 12a Fixed type 12b Movable type 14 Fixed platen 15 Movable platen 17 Tie bar 22 Toggle link 23 Mid link 24 Cross head link 25 Cross head 40 Toggle pin 40a Bush

Claims (5)

Clamping abnormality judgment of the toggle type clamping mechanism in which the movable mold attached to the movable platen is bent and extended with the movable link attached to the movable platen, and the mold is closed, clamped and opened. A method,
A dynamic strain amount of a plurality of tie bars that guide the movable plate in the mold opening / closing direction during the mold closing, the mold clamping, and the mold opening is measured by a tie bar dynamic strain amount detecting means and calculated from the dynamic strain amount. While monitoring the clamping force to be
Toggle type mold clamping mechanism for determining that the mold clamping is abnormal when the mold clamping force 1 in at least one of the initial stage and the final stage of the mold clamping state is larger than the allowable value 1 than the mold clamping force 2 in the middle stage of the mold clamping state. Mold clamping abnormality judgment method. When the first mold clamping abnormality is judged, an alarm is sent,
2. The toggle-type mold clamping mechanism according to claim 1, wherein the next cycle is not started when a difference between the mold clamping force 1 and the mold clamping force 2 is larger than an allowable value 2 at the second or later mold clamping abnormality determination. Mold clamping abnormality judgment method. Clamping abnormality judgment of the toggle type clamping mechanism in which the movable mold attached to the movable platen is bent and extended with the movable link attached to the movable platen, and the mold is closed, clamped and opened. A method,
During the mold closing, mold clamping, and mold opening, the dynamic strain amount of a plurality of tie bars that guide the movable plate in the mold opening / closing direction is measured by the tie bar dynamic strain amount detecting means, and the dynamic strain amount is monitored. As well as
Toggle type mold clamping mechanism for determining that the mold clamping is abnormal when the dynamic strain amount 1 in at least one of the initial and final stages of the mold clamping state is larger than the allowable value 1 than the dynamic strain quantity 2 in the middle period of the mold clamping state. Mold clamping abnormality judgment method. When the first mold clamping abnormality is judged, an alarm is sent,
4. The toggle type mold clamping mechanism according to claim 3, wherein the next cycle is not started when a difference between the dynamic strain amount 1 and the dynamic strain amount 2 is larger than an allowable value 2 at the second or later mold clamping abnormality determination. Mold clamping abnormality judgment method.   The said clamping abnormality is generation | occurrence | production of the state in which the said toggle link bends reversely to a normal bending direction beyond the expansion | extension state in the said mold clamping state. The method for determining a clamping abnormality of the toggle type clamping mechanism as described.

Images