JP6701278B2 - Method for detecting bush wear of toggle type mold clamping mechanism and toggle type mold clamping device - Google Patents

Description

  The present invention relates to a method for detecting wear of a bush of a toggle type mold clamping device of an injection molding machine, and a toggle type mold clamping device. More specifically, the link forming the toggle mechanism has a clevis of a mold plate. The present invention relates to a detection method for detecting wear of a bush in which the link pin is rotatably pivotally attached to the link pin, and a toggle type mold clamping device in which such a detection method is implemented. It is a thing.

  As is well known in the art, the injection molding machine is roughly configured by a mold clamping device that opens and closes a pair of molds, and an injection device that injects molten resin into the molds that have been clamped. The mold clamping device includes a so-called direct pressure type mold clamping device that generates a mold clamping force by a mold clamping cylinder, and a toggle type mold clamping device that opens and closes a mold by a toggle mechanism. The toggle type mold clamping device of the latter is excellent in that it can open and close the mold at high speed and can efficiently generate a large mold clamping force with a small driving force.

  The toggle mechanism of the toggle type mold clamping device is composed of a plurality of links, and the links are pivotally attached to the clevis of the mold board or to other links by link pins. A bush is provided on the pivot portion, and the link pin is rotatably fitted to the bush. This allows the link pin to rotate smoothly. By the way, since the bush is made of a metal having a relatively low hardness as compared with the link pin made of a metal having a high hardness, the bore of the bush is gradually worn by a long-term operation. Then, the characteristics of the toggle mechanism may slightly change, the required mold clamping force may not be obtained, and molding defects such as burrs may occur. To recover the required mold clamping force, it is necessary to readjust the mold clamping force, which is complicated. Furthermore, if the wear amount of the bush bore is uneven between the left and right links, the left and right balance may be lost when the toggle mechanism bends and stretches, resulting in abnormal noise. Doing so will damage the toggle mechanism. Therefore, it is necessary to replace the bush when it becomes worn.

JP, 10-109337, A

  Patent Document 1 describes a method of measuring the amount of wear of a bush in a toggle type mold clamping device of an injection molding machine. In the method described in Patent Document 1, a predetermined wear measuring jig is used. This jig has a plate shape with a predetermined width, and the plate width gradually decreases toward the tip near the tip, that is, near the head. That is, in the vicinity of the head, both side surfaces of the plate are slightly inclined taper surfaces, so that the vicinity of the head is formed in an inverted trapezoidal shape. Each link is provided with a link pin at one end and the other end, and the head of this jig is inserted between these two link pins. The plate width of the jig is slightly wider than the distance between the link pins at the position separated from the head. However, at the head, the plate width is shorter than the distance between the link pins. Therefore, when the head of the jig is inserted, only a predetermined amount can be inserted. When it is inserted, the tapered both side surfaces eventually come into contact with the two link pins, and the jig cannot be inserted any more. By measuring the insertion amount at this time, the distance between the link pins can be accurately measured. By the way, when the bush is worn, there is play in the bore of the bush and the link pin. In other words, the position of the link pin shifts slightly within the bore and is not stable. Then, the distance between the two link pins cannot be accurately measured. Therefore, the measurement between the link pins should be performed when the mold is clamped. This is because the position of the link pin in the bore of the bush is fixed. That is, in the method described in Patent Document 1, the toggle type mold clamping device clamps the mold, and the toggle mechanism is stopped in the mold clamped state. Then, the jig is manually inserted between the two link pins. Measure the distance between the link pins. If this distance deviates from the proper distance, it is determined that the bush is worn.

  Since the distance between the two toggle pins pivotally attached to both ends of the link can also be measured by the method described in Patent Document 1, the amount of wear of the bush can be accurately measured. That is, it can be determined whether or not the bush should be replaced. However, there are some problems to be solved. Specifically, the measurement of the amount of wear of the bush must be carried out by stopping the molding cycle in the injection molding machine and manually. Since the productivity decreases when the molding cycle is stopped, it cannot be carried out frequently. If this happens, the detection of bush wear may be delayed, and molding defects such as burrs may occur. There are safety issues with performing the inspection manually. It is necessary to stop the toggle type mold clamping device in the mold clamping state, open the safety cover in this state, and put an operator in the toggle mechanism. It can be said that the danger is great. Further, although the method described in Patent Document 1 is used to inspect in a mold clamped state, it can be said that there is no guarantee that the link pin is fixed in the bore of the bush. If the bushing bore wear progresses after the mold clamping adjustment has been performed and the molding cycle is repeated without adjusting for a long period of time, sufficient mold clamping force may not be generated even if the mold clamping device clamps the mold. .. This is because, in such a case, the position of the link pin in the bore of the bush may become unstable even in the mold clamped state. Then, the amount of wear of the bush cannot be accurately measured.

  The present invention solves the above problems, and an object of the present invention is to provide a bush wear detection method of the toggle mechanism of the injection molding machine, specifically, it is not necessary to stop the molding cycle, safely Moreover, it is an object of the present invention to provide a bush wear detecting method capable of surely detecting the wear of the bush.

  According to the present invention, a link that constitutes a toggle mechanism is pivotally attached to a clevis provided on a mold board by a link pin so that the link pin is inserted, and a bush into which the link pin is inserted is provided. The method is to detect the wear of the bush for the toggle type mold clamping device. In the present invention, a marker is provided at the end of the link pin and an optical sensor is provided on the template. In addition, a tie bar sensor is installed on the tie bar near the clevis. During mold clamping in the molding cycle, the tie bar elongation is detected to confirm that the mold clamping force is being generated. At this time, the position of the marker is detected by the optical sensor, and it is determined whether or not the marker deviates from the predetermined reference position. If the deviation is large, it is judged that the bush is worn.

Thus, in order to achieve the above object, the invention according to claim 1 pivotally attaches a link constituting a toggle mechanism to a clevis provided on a mold plate by a link pin, and In a toggle type mold clamping device provided with a bush into which the link pin is inserted in the attachment part, a detection method for detecting wear of the bush, wherein a marker is provided at an end of the link pin, An optical sensor is provided near the clevis, and a tie bar sensor is provided at a tie bar located near the clevis of the toggle type mold clamping device, and the position of the marker is detected by the optical sensor during mold clamping in the molding cycle. With the extension of the tie bar is detected, it is confirmed that the mold clamping force is generated from the extension of the tie bar, the deviation amount from the predetermined reference position for the position of the marker is detected, thereby the The method is configured as a bush wear detection method for a toggle type mold clamping device, which is characterized by determining the amount of wear.
In the invention according to claim 2, the left and right first and second links constituting the toggle mechanism are formed by the first and second link pins with respect to the first and second clevis provided on the left and right of the mold board. A toggle-type mold clamping device provided with first and second bushes which are pivotally pivotally mounted and in which the first and second link pins are inserted, wherein the first and second bushes are provided. Of the first and second link pins, and first and second markers near the first and second clevis of the template, respectively. When the mold clamping of the molding cycle is performed, the optical sensor of No. 1 and the tie bar sensors of No. 1 and No. 2 of the toggle type mold clamping apparatus are provided at the first and second tie bars respectively located near the first and second clevis. In the above, the positions of the first and second markers are detected by the first and second optical sensors, and the elongation of the first and second tie bars is detected, and the mold clamping force is calculated from the elongation of the first and second tie bars. Is detected, the amount of deviation of the positions of the first and second markers from a predetermined reference position is detected, and thereby the amount of wear of the first and second bushes is determined. And a bush wear detection method for a toggle type mold clamping device.
According to a third aspect of the present invention, the link forming the toggle mechanism is pivotally attached to the clevis provided on the template by a link pin so that the link pin is inserted into the pivot portion. A toggle type mold clamping device of an injection molding machine provided with a bush, wherein a marker is provided at an end of the link pin, an optical sensor for detecting a position of the marker is provided at the mold plate, and the toggle type. A tie bar sensor is provided in each of the tie bars located near the clevis of the mold clamping device, and is configured as a toggle type mold clamping device.
In the invention according to claim 4, the first and second links forming the toggle mechanism can be rotated by the first and second link pins with respect to the first and second clevis provided on the left and right of the mold board. A toggle-type mold clamping device, which is pivotally attached to the first and second bushes into which the first and second link pins are inserted, the toggle die clamping device comprising: Have first and second markers at the ends thereof, first and second optical sensors for detecting the positions of the first and second markers, and the first of the toggle type mold clamping device. The first and second tie bars located respectively near the two clevis are provided with the first and second tie bar sensors, respectively, and are configured as a toggle type mold clamping device.

  INDUSTRIAL APPLICABILITY As described above, according to the present invention, the link that constitutes the toggle mechanism is pivotally attached to the clevis provided on the mold plate by the link pin so that the link pin can be inserted into the bush. In the toggle type mold clamping device provided with, it is configured as a detection method for detecting wear of the bush. The present invention provides a marker at the end of the link pin, an optical sensor near the clevis of the mold plate, and a tie bar sensor at the tie bar near the clevis of the toggle type mold clamping device. At the time of clamping, the optical sensor detects the position of the marker and the extension of the tie bar, confirms that the mold clamping force is generated from the extension of the tie bar, and the amount of deviation of the marker position from the predetermined reference position Is detected, and the amount of wear of the bush is determined accordingly. Therefore, in the present invention, when the mold is clamped in the molding cycle, the amount of wear of the bush is detected by confirming that the mold clamping force is reliably generated, so that it is carried out with the link pin securely fixed. It will be. That is, the amount of wear can be accurately detected. Further, there is no need to stop the molding cycle, and the excellent effect that the productivity is not affected is obtained. Further, since the detection can be carried out for each molding cycle, there is no fear of continuing the molding cycle without noticing that the wear amount exceeds the allowable range. That is, if it is detected that the allowable range is exceeded, the injection molding machine may be stopped at a necessary timing and the bushes may be replaced, so that defective molding such as burrs can be prevented. Further, since the detection of the amount of wear of the bush is performed by the optical sensor, it is not necessary for the operator to manually operate. In other words, it is safe. In another invention, the first and second links constituting the toggle mechanism are pivotally attached to the first and second clevis provided on the left and right of the mold board by the first and second link pins. In a toggle type mold clamping device in which first and second bushes into which first and second link pins are inserted are provided in the pivotally attached portion, a detection method for detecting wear of the first and second bushes is provided. .. Then, the first and second markers are respectively attached to the ends of the first and second link pins, the first and second optical sensors are respectively provided in the vicinity of the first and second clevis of the mold board, and the toggle type mold clamping device is provided. First and second tie bar sensors are provided on the first and second tie bars respectively located near the first and second clevis, and the first and second optical sensors are used to perform the first and second tie bar sensors during mold clamping in the molding cycle. Position of the first and second tie bars is detected while confirming that the mold clamping force is generated from the extension of the first and second tie bars, and the positions of the first and second markers are detected. The amount of deviation from the predetermined reference position is detected, and the amount of wear of the first and second bushes is determined based on the detected amount. That is, it is possible to detect the amount of wear of the left and right bushes of the toggle mechanism, that is, the first and second bushes, and thereby determine the balance of the left and right wear amounts. If only one of the bushes has a large amount of wear, an abnormal noise may occur when the toggle mechanism is bent and stretched to open and close the mold. If the imbalance of the wear amount of the first and second bushes can be detected early, such abnormal noise can be prevented. In addition, according to the present invention, it is possible to detect a case where there is a problem in the parallelism of the mold, for example. That is, when the amounts of expansion of the first and second tie bars are different, it can be estimated that there is a problem with the parallelism of the mold.

It is a front view showing a vertical injection molding machine concerning an embodiment of the invention in a partial section. FIG. 2 is a diagram showing a part of a toggle mechanism of the toggle type mold clamping device according to the present embodiment, showing a clevis formed on a mold board and a part of a link pivotally attached to the clevis by a link pin. It is sectional drawing shown. It is a figure which shows a part of toggle mechanism of the toggle type mold clamping device which concerns on this Embodiment, (a) shows the clevis formed in the mold board and the link pin pivotally attached to the clevis. (A) is a front view showing a clevis, a link pivotally attached to the clevis, and a link pin, respectively.

  The present embodiment will be described below. As shown in FIG. 1, a vertical injection molding machine 1 according to the present embodiment includes a toggle type mold clamping device 2 and an injection device 3 provided above the toggle type mold clamping device 2. It consists of The toggle type mold clamping device 2 includes a fixed platen 5 supported by predetermined members 4 and 4 of a housing, an upper movable platen 6 arranged above the fixed platen 5, and a fixed platen 5 below the fixed platen 5. A plurality of tie bars 9A, 9B,..., Which are arranged to connect the upper movable plate 6 and the lower movable plate 7 slidably through the lower movable plate 7 and the fixed plate 5, and the fixed plate 5. The toggle mechanism 10 is provided between the lower movable plates 7. A lower mold 12 is provided on the upper surface of the fixed platen 5, and an upper mold 13 is provided on the lower surface of the upper movable platen 6. When the toggle mechanism 10 is driven, these molds 12, 13 are opened and closed. Has become. A hollow 6a is opened in the center of the upper movable platen 6, the injection device 3 is inserted from above, and an injection nozzle of the injection device 3 is in contact with a sprue (not shown) of the upper mold 13.

  The toggle mechanism 10 is symmetrically configured and includes a plurality of links and the like. Hereinafter, the equivalent members provided on the left and right sides will be referred to as "first" for the right side member and "second" for the left side member, respectively. Then, the toggle mechanism 10 is composed of the first and second lower links 15A and 15B, the first and second upper links 16A and 16B, the first and second cross links 18A and 18B, the cross head 19, and the like. Thus, it is provided between the two mold plates, that is, between the lower movable plate 7 and the fixed plate 5. The first and second lower links 15A and 15B are respectively connected to the first and second lower clevis 17A and 17B whose one end is formed on the left and right of the lower movable plate 7, respectively. It is pivotally supported, that is, pivotally mounted by pins 21A and 21B. One end of each of the first and second upper links 16A and 16B has first and second upper link pins 22A, which correspond to the first and second upper clevis 26A and 26B formed on the left and right of the fixed platen 5, respectively. 22B is pivotally attached. The other ends of the first and second upper and lower links 16A and 15B are rotatably connected, that is, pivotally attached to each other by the first and second middle link pins 23A and 23B. The first and second lower links 15A and 15B according to the present embodiment are formed with protrusions laterally protruding by a predetermined length in the vicinity of the first and second middle link pins 23A and 23B. One end of each of the cross links 18A and 18B is pivotally attached to the first and second lower links 15A and 15B by the first and second cross link pins 24A and 24B. The other ends of the cross links 18A, 18B are pivotally attached to the crosshead 19 by first and second crosshead pins 25A, 25B.

  By the way, each link pin in the toggle mechanism 10, that is, the first and second lower link pins 21A and 21B, the first and second upper link pins 22A and 22B, the first and second middle link pins 23A and 23B, the first and second link pins. The cross link pins 24A, 24B and the first and second cross head pins 25A, 25B are all inserted into the bush at their pivot points. Although bushes are not shown in FIG. 1, in detail, the bushes are inserted into the holes formed in each link 15A, 16A,... Or clevis 17A, 26A,. It is rotatably inserted in the bore. Since the bush is made of a metal having a hardness lower than that of the link pin, if the link pin rotates under a load, the bore will wear due to long-term operation. Of these bushes, the first and second lower link pins 21A and 21B, on which the mold clamping force acts, the first and second upper link pins 22A and 22B, and the first and second middle link pins 23A and 23B, are provided. Wear is particularly fast in the inserted bush. Therefore, in the present embodiment, a detection device that detects wear of the bushes provided on the first and second lower link pins 21A and 21B, that is, the first and second bushes is provided. The detection device includes first and second markers 28A and 28B provided on the ends of the first and second lower link pins 21A and 21B, and first and second optical sensors provided on the lower movable plate 7. 29A and 29B. The marker on the right side of FIG. 1, that is, the first marker 28A is shown in FIG. The male screw 28b is screwed onto the female screw opened at the center. The left marker in FIG. 1, that is, the second marker 28B is also provided on the second lower link pin 21B. Note that FIG. 2 also shows that the first bush 30A is provided on the first lower clevis 17A of the lower movable platen 7.

  In the present embodiment, the first and second optical sensors 29A and 29B are laser displacement meters. The laser displacement meter itself irradiates the first and second markers 28A and 28B with laser to detect reflected light, and thereby measures the positions of the first and second markers 28A and 28B. The laser displacement meter has high measurement accuracy and can measure the positions of the first and second markers 28A and 28B with an accuracy of, for example, 0.2 μm to several μm. As will be described later, by accurately measuring this position, it is possible to measure the wear amount of the first and second bushes 30A and 30B. If the position can be detected optically, that is, it can be detected in a non-contact manner and the measurement accuracy is high, the first and second optical sensors 29A and 29B can be composed of other types of optical sensors.

  In the toggle type mold clamping device 2, the crosshead 19 is provided with a ball screw 31, and a ball nut 32 is screwed onto the ball screw 31. The ball nut 32 is rotatably provided on the lower movable plate 7 and is rotated by a drive mechanism not shown in FIG. Therefore, when the ball nut 32 is rotated by the drive mechanism, the ball screw 31 moves up and down and the cross head 19 is driven. Then, the toggle mechanism 10 bends and extends to open and close the toggle type mold clamping device 2.

  When the respective tie bars 9A and 9B located near the first and second lower clevis 17A and 17B of the lower movable plate 7 are referred to as first and second tie bars 9A and 9B, respectively, these first and second tie bars 9A and 9B is provided with strain sensors, that is, first and second tie bar sensors 37A and 37B. Thereby, the elongations of the first and second tie bars 9A and 9B can be measured, and it can be confirmed that the mold clamping force is generated.

  Hereinafter, the bush wear detection method according to the present embodiment will be described. Wear of the bores of the first and second bushes 30A and 30B progresses mainly during mold clamping. For example, with respect to the first bush 30A on the right side of the toggle mechanism 10, since wear progresses in the direction in which the first lower link pins 21A and 21B are pressed during mold clamping, the bore is shown in FIG. It changes into an elliptical shape. As the wear progresses, a play 35 is formed between the bore of the first bush 30A and the first lower link pin 21A. Then, the position of the first lower link pin 21A becomes unstable in the bore. Therefore, the bush wear detection method according to the present embodiment is performed during mold clamping. The toggle mechanism 10 is extended and clamped. The extension of the first tie bar 9A is detected by the first tie bar sensor 37A. This confirms that the mold clamping force is properly generated. When the mold clamping force is appropriately generated, the first lower link 15A is pressed downward by the mold clamping force as shown in FIG. 3B, whereby the first lower link pin 21A is moved downward. Pressed against. Then, the position of the first lower link pin 21A is fixed in the bore of the first bush 30A. At this time, the position of the first marker 28A is measured by the first optical sensor 29A. The position of the first marker 28A detects a reference position during mold clamping, that is, a deviation from the reference position. If the amount of this deviation exceeds a predetermined threshold value, it is determined that the first bush 30A is worn. A bush (not shown) of the injection molding machine 1 is informed of the wear of the bush and a message indicating that the bush needs to be replaced is displayed. By the way, in the present embodiment, it is confirmed that the mold clamping force is appropriately generated also in the second tie bar 9B, and the second bush 30B on the left side of the toggle mechanism 10 also has the second optical sensor. The wear is determined by 29B and the second marker 28B. This makes it possible not only to measure the amount of wear of the first and second bushes 30A and 30B, but also to check the balance of wear. Furthermore, it is possible to check whether the molds are properly parallel. That is, when the first tie bar 9A has a smaller elongation than the second tie bar 9B, it is expected that there is a problem in the parallelism of the mold. A message to that effect is displayed on the monitor.

  The bush wear inspection method for the toggle type mold clamping device according to the present embodiment can be variously modified. For example, the frequency of inspection can be changed. Although the present embodiment has been described as being performed every molding cycle, it may be performed every predetermined number of molding cycles. The bush subjected to the wear inspection may be changed to another bush. For example, when detecting wear of the bushes of the first and second upper link pins 22A and 22B, markers are provided on the first and second upper link pins 22A and 22B, respectively. Then, the fixed plate 5 is provided with optical sensors near the first and second upper clevis 26A and 26B, respectively. If the positions of the markers of the first and second upper link pins 22A and 22B are detected during mold clamping, the amount of wear of the bushes provided on these can be determined. The wear may be detected only on one of the first and second bushes 30A and 30B. In this case, if the wear amount of one bush to be inspected exceeds the allowable amount, it may be determined that the other bushes are about to be replaced.

  The bush wear inspection method for the toggle type mold clamping device according to the present embodiment can be implemented not only in the vertical injection molding machine 1 but also in a general injection molding machine that is placed horizontally on a bed. In such an injection molding machine, the toggle mechanism is provided between the movable plate and the mold clamping housing. The mold clamping housing corresponds to the lower movable plate in the vertical injection molding machine, which can also be called a mold plate. A marker is provided at the end of the link pin pivotally attached to the mold plate, that is, the clevis provided on the movable plate or the mold clamping housing, and an optical sensor is provided near the clevis on the mold plate. If a sensor is provided, wear of the bush into which this link pin is inserted can be detected.

1 Vertical Injection Molding Machine 2 Mold Clamping Device 3 Injection Device 4 Case Member 5 Fixed Plate 6 Upper Movable Plate 7 Lower Movable Plate 9 Tie Bar 10 Toggle Mechanism 12 Lower Mold 13 Upper Mold 15 Lower Link 16 Upper Link 17 Lower clevis 18 Cross link 19 Cross head 21 Lower link pin 22 Upper link pin 23 Middle link pin 24 Cross link pin 25 Cross head pin 26 Upper clevis 28 Marker 29 Optical sensor 30 Bush 37 Tie bar sensor

Claims (4)

A toggle type mold in which a link constituting a toggle mechanism is pivotally attached to a clevis provided in a mold plate by a link pin, and a bush into which the link pin is inserted is provided in the pivot portion. In the fastening device, a detection method for detecting the wear of the bush,
A marker is provided at an end of the link pin, an optical sensor is provided near the clevis of the mold plate, and a tie bar sensor is provided at a tie bar of the toggle mold clamping device near the clevis. At the time of clamping, the optical sensor detects the position of the marker and the extension of the tie bar, and it is confirmed that the mold clamping force is generated from the extension of the tie bar, and the marker has a predetermined reference position. A bush wear detecting method for a toggle type mold clamping device, characterized in that the amount of deviation from a position is detected and the amount of wear of the bush is judged based on the detected amount. The left and right first and second links forming the toggle mechanism are rotatably pivoted to the first and second clevis provided on the left and right of the mold board by the first and second link pins. A toggle-type mold clamping device in which first and second bushes, into which the first and second link pins are inserted, are provided in a pivot portion, which is a detection method for detecting wear of the first and second bushes. hand,
First and second markers are respectively provided at the ends of the first and second link pins, first and second optical sensors are provided near the first and second clevis of the mold plate, and the toggle type mold clamping is performed. First and second tie bar sensors are provided on the first and second tie bars respectively located in the vicinity of the first and second clevis of the apparatus, and the first and second optical sensors are used for clamping the mold in the molding cycle. Detecting the positions of the first and second markers and detecting the extension of the first and second tie bars, and confirming that the mold clamping force is generated from the extension of the first and second tie bars, Bush wear detection of a toggle type mold clamping device, characterized in that the amount of deviation of a position of the first and second markers from a predetermined reference position is detected to determine the amount of wear of the first and second bushes. Method. An injection molding machine in which a link forming a toggle mechanism is pivotally attached to a clevis provided on a mold board by a link pin so that the link pin is inserted into the bush. A toggle type mold clamping device of
A marker is provided at the end of the link pin, an optical sensor for detecting the position of the marker is provided on the mold plate, and a tie bar sensor is provided for a tie bar located near the clevis of the toggle type mold clamping device. A toggle-type mold clamping device characterized by being provided. The first and second links forming the toggle mechanism are rotatably pivoted to the first and second clevis provided on the left and right of the mold board by the first and second link pins. A toggle-type mold clamping device having first and second bushes into which the first and second link pins are inserted,
First and second markers are provided at the ends of the first and second link pins, first and second optical sensors for detecting the positions of the first and second markers are provided on the template, and the toggle is provided. Toggle type mold clamping device, characterized in that first and second tie bar sensors are respectively provided on the first and second tie bars located near the first and second clevis of the mold clamping device. .

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