JP5770249B2 - Injection molding machine provided with means for measuring tilt of driven mechanism using image measuring device - Google Patents

Description

  The present invention relates to an injection molding machine, and more particularly to an injection molding machine provided with means for measuring the inclination of a driven mechanism using an image measuring device.

  When a molded product is manufactured using an injection molding machine, each of the power transmission mechanisms having a plurality of driven mechanisms that convert rotational motion into linear motion due to erroneous setting of molding conditions and / or erroneous operation of an operator, There may be a difference in the driving force of the driven mechanism. When this driving force difference exceeds a certain threshold, the driving force must be adjusted. The reason is that a defect occurs in a ball screw, a bearing, or the like that is a component of the driven mechanism due to a difference in driving force.

  When a motor is directly connected as a driving device for the driven mechanism, the output of the motor may be adjusted. However, when a plurality of driven mechanisms are driven by a single motor via a timing belt or the like, a means for measuring the driving force of the driving device by attaching a driving force detecting means such as a strain gauge to the driving device of the driven mechanism If the drive mechanism of the driven mechanism is not installed, or if a sensor or the like is provided in each of the driven mechanism drive devices and the meshing relationship between the timing belt and the driven mechanism pulley is not checked by the attached sensor, the driving force of the driven mechanism I do n’t know if there is any difference.

  In Patent Document 1, a motor is directly connected as a drive device for a driven mechanism, and in an injection molding machine having a mechanism for moving a driven object back and forth by a plurality of axes, the axial force of each axis is detected, and the axial force of each axis is detected. A technique of an injection molding machine that can adjust a load balance between each axis when a difference occurs is disclosed.

  Patent Document 2 discloses a driven pulley in a molding apparatus in which a driving force is transmitted from one motor to a plurality of driven shafts via a timing belt, and a movable portion is moved by rotation of the plurality of driven shafts. A technique of a molding apparatus capable of detecting a tooth jump is disclosed.

JP 2007-136961 A JP 2010-284931 A

  As described in the prior art, when a motor and a driving device having a plurality of driven mechanisms are coupled and driven by transmission means such as a belt, the driving force is detected by a strain gauge or the like. Like an ejector mechanism, a space for mounting a detector such as a strain gauge is limited, and each drive device needs to be considered in order to move. In addition, there is a method of attaching a sensor to a plurality of driving devices and measuring the deviation between the driven mechanism and the driving device by the sensor. I must.

  Accordingly, an object of the present invention is to provide an injection molding machine provided with means for detecting an abnormality of a power transmission mechanism using an image measuring device in order to solve the above-mentioned problems of the prior art. Then, it is to provide a tooth jump detection method of an injection molding machine using means for detecting an abnormality of the power transmission mechanism.

The invention according to claim 1 of the present application includes a power transmission mechanism having a plurality of driven mechanisms for converting a rotational motion into a linear motion, a movable member on which the power transmission mechanism is mounted, and a motor for driving the power transmission mechanism. have a, and the power transmission mechanism, a motor, wherein the power transmission mechanism to drive the power transmission mechanism and a movable member that is mounted, in an injection molding machine to be mounted on a movable platen for mounting a movable mold, An image measuring device that images the movable member and measures the inclination of the imaged movable member with respect to the movable platen, and an allowable value in which a value of the inclination of the movable member measured by the image measuring device is set in advance. And an abnormality signal output means for notifying that an abnormality has occurred in the power transmission mechanism.
The invention according to claim 2 includes normal image storage means for storing an image of the movable member captured by the image measurement device as a normal image when the movable member is in a normal state, and the image measurement device includes: 2. The injection according to claim 1, wherein an inclination of the movable member is obtained by comparing an image of the movable member captured every predetermined number of molding cycles with a normal image stored in the normal image storage unit. It is a molding machine.

The invention according to claim 3 is a power transmission mechanism having a plurality of driven mechanisms for converting rotational motion into linear motion, a movable member to which the power transmission mechanism is mounted, a motor for driving the power transmission mechanism, a belt for transmitting the rotary motion of the motor to the plurality of driven mechanisms, imaging the movable member, possess an image measuring device for measuring the inclination of the movable member that is imaging, and the power transmission mechanism, wherein A movable member on which a power transmission mechanism is mounted, a motor that drives the power transmission mechanism, and a belt that transmits the rotational motion of the motor to the plurality of driven mechanisms are mounted on a movable platen on which a front movable mold is mounted. in tooth jump detection method of the belt of the driven mechanism of an injection molding machine which is a first step of measuring the inclination with respect to the movable platen of the movable member, the movable portion and the measurement If the inclination of the movable member exceeds the preset allowable value as a result of the second step of comparing the inclination of the movable member with a preset allowable value and the comparison by the second step, the tooth jump of the belt And a third step of determining a tooth jump detection method for an injection molding machine.

  According to the present invention, it is possible to provide an injection molding machine provided with means for detecting abnormality of a power transmission mechanism using an image measuring device. Further, it is possible to provide a method for detecting tooth jump of an injection molding machine using means for detecting an abnormality of the power transmission mechanism.

It is a figure explaining the principal part of the injection molding machine provided with the means to measure the inclination of a movable member. It is a figure explaining the force added to an ejector plate at the time of protrusion of a molded article. It is a figure explaining the example which measures the inclination of a movable member by measuring the space | interval of the predetermined location of a movable member and a reference | standard plate. It is a figure explaining the flow of the process which confirms the inclination of a movable member (ejector plate) for every shot. It is a figure explaining the example which measures the inclination of a movable member by the comparison with a normal image and the present image. It is a figure explaining the flow of the process which compares the movable member (ejector plate) of a normal image and the present image, and confirms the inclination of a movable member (ejector plate).

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a view for explaining a main part of an injection molding machine provided with means for measuring the inclination of a movable member. In FIG. 1, the principal part of the injection molding machine provided with the abnormality detection function of the power transmission mechanism in the eject mechanism is shown. The injection molding machine includes an injection unit for injecting resin into the mold, a mold clamping unit for clamping the mold, and a control device for controlling the entire injection molding machine. In the following description, an embodiment of the present invention will be described based on the mold clamping unit. Note that a control device that controls the entire injection molding machine includes a processor, a memory, a display device, and a signal input device, as in a conventionally known device.

  The fixed platen 1 and the rear platen 2 are connected by a plurality of tie bars 4, and the movable platen 3 is installed so as to be movable along the tie bars 4. A fixed mold 5 a is attached to the fixed platen 1, and a movable mold 5 b is attached to the movable platen 3. A mold opening / closing mechanism 7 is installed on the rear platen 2, and the mold opening / closing mechanism 7 drives the movable platen 3 via a toggle mechanism 8 to open / close and mold / clamp the fixed mold 5 a and the movable mold 5 b. The rear platen 2 moves forward and backward with respect to the fixed platen 1 by a mold thickness adjusting motor 9, and a position corresponding to the thickness of the mold can be set.

  The movable platen 3 is provided with an ejector mechanism 6 for ejecting a molded product. Next, the molded product ejection operation of the ejector mechanism 6 will be described. A toothed belt 13 is hung on a driving pulley 11 coupled to an ejector servomotor 10 and two driven pulleys 12a and 12b coupled to two ball screws 14a and 14b. The shaft is rotatably fixed to the movable platen 3 via bearing housings 16a and 16b. Drive-side bearings 17a and 17b are mounted in the bearing housings 16a and 16b.

  The nuts of the ball screws 14 a and 14 b are coupled to a plate called an ejector plate (knockout bar) 15, and several ejector pins 18 are attached to the ejector plate (knockout bar) 15. When the ejector servo motor 10 rotates, the driving pulley 11 rotates, the toothed belt 13 hung on the driving pulley 11 rotates, and the driven pulleys 12a and 12b are rotated by the rotation of the toothed belt 13. . The ball screws 14a and 14b are rotated by the rotation of the driven pulleys 12a and 12b, and the ejector plate (knockout bar) 15 coupled to the nut moves forward and backward in the axial direction. The ejector pin 18 attached to the ejector plate (knockout bar) 15 moves forward and backward in the axial direction, moves the die side ejector plate 19 in the movable die 5b back and forth, and is attached to the die side ejector plate 19 A pin sticks out a molded product.

  When ejecting the molded product, the ejector pin 18 receives a reaction force from the molded product. The load received by the ejector pin 18 is transmitted to the bearing housings 16a and 16b through the ejector plate (knockout bar) 15 and the ball screws 14a and 14b. At this time, the bearing housings 16a and 16b are distorted in proportion to the load. Since the ejector plate (knockout bar) 15 and the mold surface of the movable platen 3 are adjusted to be parallel so that the load applied to the two ball screws 14a and 14b is equal when the machine is assembled, the bearing surface is adjusted. The strains of the housings 16a and 16b are uniform.

However, when there is an abnormality such as tooth skipping of the toothed belt with one ball screw, the parallelism between the ejector plate (knockout bar) 15 and the mold surface of the movable platen 3 is broken (that is, it is inclined as compared with a normal state). ). Then, as shown in FIG. 2, in addition to the reaction force F when projecting the molded article, joined by a reaction force F _M by moment M inclined ejector plate (knockout bars) 15 is about to be returned in parallel, 2 The load applied to the ball screws 14a and 14b is not uniform. Therefore, the distortion of the bearing housings 16a and 16b is not uniform.

  By measuring the state in which the ejector plate 15 is not parallel to the mold surface of the movable platen 3, that is, by measuring the inclination of the ejector plate 15, it is possible to detect the occurrence of tooth jump of the toothed belt.

  Therefore, in the embodiment of the present invention, the image measuring device 20 is used to measure the inclination of the ejector plate 15. The image measuring device 20 is installed on the upper surface or lower surface, the operation side, or the non-operation side of the injection molding machine that can image the ejector plate 15. The image measurement device 20 calculates the inclination of the ejector plate 15 by calculation based on the captured image of the ejector plate 15. In addition, the inclination of the ejector plate 15 is an inclination with respect to the mold mounting surface. The control device 30 controls the entire injection molding machine and executes an injection molding cycle. The control device 30 may have a function of calculating the inclination of the ejector plate 15.

  The control device 30 transmits an abnormality detection signal when the inclination of the ejector plate 15 calculated by the image measuring device exceeds a preset value set by the input device 31. An abnormality signal transmitted from the control device 30 is received by an alarm device 32 such as an alarm lamp, and an abnormality is notified to an operator by lighting a lamp or the like, or is received inside the control device 30 and controlled by the control device 30. It is used to perform the process of forcibly stopping.

  By measuring the image of the ejector plate 15, the inclination of the ejector plate 15 to which a plurality of driven mechanism drive devices are attached can be measured by the method described in the following (1) and (2).

(1) Measure the inclination of the movable member by measuring the distance between the movable member and the reference plate and FIG. 3 shows an example of measuring the inclination of the movable member. The inclination of the ejector plate 15 which is an example of a movable member is measured. As shown in FIG. 3, the distance between two points between the driven plate and the reference plate to which the driven mechanism is fixed at right angles to the moving direction of the driven plate is measured. The distance between the ejector plate 15 as the driven plate and the ball screw mounting seat surface 3a of the movable platen 3 as the reference plate is measured. In order to measure the inclination of the movable platen 3 of the ejector plate 15 with respect to the ball screw mounting seat surface 3a, as shown in the figure, the movable platen 3 at two different locations (measurement position P1 and measurement position P2) of the ejector plate 15 is shown. The distance between the ball screw mounting seat surface 3a is measured.

  When the ejector plate 15 is not inclined with respect to the ball screw mounting seat surface 3a of the movable platen 3 (normal state), the ejector plate 15 and the ball screw mounting seat surface 3a of the movable platen 3 at the measurement position P1 and the measurement position P2 Both are separated by T. When tooth jump occurs in one ball screw, the ejector plate 15 is inclined with respect to the moving direction. Therefore, for example, as shown in FIG. 3, the separation distance at the measurement position P1 is T-ΔT, and the separation distance at the measurement position P2 is T-ΔT.

  Therefore, the image measuring device 20 images the separation distance between the ejector plate 15 and the ball screw mounting seat surface 3a of the movable platen 3 at the measurement position P1 and the measurement position P2. In the image measuring apparatus 20, the distance between the measurement position P1 and the measurement position P2 is obtained, and the distance is compared to determine whether or not the ejector plate 15 is tilted. Then, the determination result is sent to the control device 30. Note that the image measurement device 20 may be simply used as an imaging unit, and the control device 30 may execute the calculation of the separation distance and the determination of the inclination.

FIG. 4 is a diagram for explaining the flow of processing for confirming the inclination of the movable member (ejector plate) for each shot. Hereinafter, it demonstrates according to each step.
[Step sa01] Check the inclination of the ejector plate. The confirmation of the ejector plate 15 (that is, the inclination value of the ejector plate 15 is obtained) is performed by the above-described method.
[Step sa02] It is determined whether or not the inclination value of the ejector plate exceeds a preset allowable value. If it exceeds (YES), the process proceeds to step sa03, and if it does not exceed (NO). Shifts to step sa04.
● [Step sa03] An alarm is issued and the machine is stopped.
[Step sa04] Each step of injection, holding pressure, measurement (cooling), mold opening, and protrusion is executed to complete one molding cycle.
[Step sa05] It is determined whether or not the molding cycle is to be continued. If the molding cycle is to be continued (YES), the process returns to step sa01 to continue the processing. If not (NO), the processing is terminated.

(2) Measuring the inclination of the movable member by comparing the normal image with the current image First, as shown in FIG. 5, the image of the plate (ejector plate 15) to which the driven mechanism immediately after adjustment is fixed is set as the normal image. The tilt of the movable member can be measured by superimposing the current plate images after operation and comparing the two images and measuring the deviation of the images.

  The image measuring device 20 captures in advance an image (normal image) when the ejector plate 15 is in a normal posture, and stores it in a memory of the image measuring device 20 (not shown). Next, in each molding cycle, the ejector plate 15 is imaged by the image measuring device 20 at a predetermined time when one molding cycle is completed. The image measurement device 20 compares the normal image stored in advance in the ejector plate 15 with the captured image of the ejector plate 15 captured in each molding cycle, and obtains the inclination of the ejector plate 15. Note that the control device 30 may have a function of comparing the normal image of the ejector plate 15 and the captured image of the ejector plate 15 and obtaining the inclination of the ejector plate 15.

FIG. 6 is a diagram illustrating a flow of processing for confirming the inclination of the movable member (ejector plate) by comparing the movable member (ejector plate) of the normal image and the current image. Hereinafter, it demonstrates according to each step.
[Step sb01] The normal image of the movable member is compared with the current image to confirm the inclination of the ejector plate.
[Step sb02] It is determined whether or not the inclination value of the ejector plate exceeds a preset allowable value. If it exceeds (YES), the process proceeds to step sb03, and if it does not exceed (NO). Shifts to step sb04.
● [Step sb03] An alarm is issued and the machine is stopped.
[Step sb04] The steps of injection, holding pressure, metering (cooling), mold opening, and protrusion are executed to complete one molding cycle.
[Step sb05] It is determined whether or not the molding cycle is to be continued. If the molding cycle is to be continued (YES), the process returns to step sb01, and if not (NO), the processing is terminated.

  The inclination of the movable member can be determined from the measured value of the inclination of the movable member obtained in (1) or (2) or both. When the measured value of the tilt of the movable member by (1) or (2) or both exceeds a preset allowable value, it is determined that the tooth is skipped, an alarm is issued, and the normal state is restored. Is possible.

  In the above-described embodiment of the present invention, the case of the ball screw 14 of the ejector mechanism provided in the injection molding machine has been described, but the present invention can be similarly applied to a mold screw shaft or a ball screw of an injection shaft. In the embodiment of the present invention, the motor and the ball screw are connected by a pulley and a belt, but the present invention can also be applied to a connection by a chain and a sprocket or a connection by a gear. The present invention can also be applied to the case where the number of ball screws is three or more.

DESCRIPTION OF SYMBOLS 1 Fixed platen 2 Rear platen 3 Movable platen 3a Ball screw mounting seat surface 4 Tie bar 5a Fixed side mold 5b Movable side mold 6 Ejector mechanism 7 Mold opening / closing mechanism 8 Toggle mechanism 9 Mold thickness adjusting motor 10 Ejector servo motor 11 Drive side pulley 12a driven pulley 12b driven pulley 13 toothed belt 14a driven ball screw 14b driven ball screw 15 mold side ejector plate 16a bearing housing 16b bearing housing 17a driven side bearing 17b driven side bearing 18 ejector pin 19 ejector plate 20 image measuring device

30 Control device 31 Input device 32 Alarm device

Claims (3)

Possess a power transmission mechanism having a plurality of driven mechanism for converting a rotary motion into linear motion, and a movable member to which the power transmission mechanism is mounted, a motor that drives the power transmission mechanism,
In the injection molding machine, the power transmission mechanism, a movable member on which the power transmission mechanism is mounted, and a motor that drives the power transmission mechanism are mounted on a movable platen that mounts a movable mold.
An image measuring device that images the movable member and measures the inclination of the imaged movable member with respect to the movable platen, and an allowable value in which a value of the inclination of the movable member measured by the image measuring device is set in advance. Is exceeded, an abnormal signal output means for notifying that an abnormality has occurred in the power transmission mechanism,
An injection molding machine characterized by comprising: Normal image storage means for storing, as a normal image, an image of the movable member captured by the image measuring device when the movable member is in a normal state;
With
The image measuring device compares the image of the movable member imaged every predetermined number of molding cycles with a normal image stored in the normal image storage means to determine the inclination of the movable member. The injection molding machine according to 1. A power transmission mechanism having a plurality of driven mechanisms for converting rotational motion into linear motion; a movable member on which the power transmission mechanism is mounted; a motor for driving the power transmission mechanism; and a plurality of rotational motions of the motor. a belt for transmitting the driven mechanism, imaging the movable member, possess an image measuring device for measuring the inclination of the movable member which is image pickup,
The power transmission mechanism, a movable member on which the power transmission mechanism is mounted, a motor that drives the power transmission mechanism, and a belt that transmits the rotational motion of the motor to the plurality of driven mechanisms are a front movable side mold. In the belt tooth jump detection method of the driven mechanism of an injection molding machine mounted on a movable platen mounted with
A first step of measuring an inclination of the movable member with respect to the movable platen ;
A second step of comparing the measured inclination of the movable member with a preset allowable value;
As a result of the comparison in the second step, when the inclination of the movable member exceeds the preset allowable value, a third step of determining skipping of the belt;
A tooth jump detection method for an injection molding machine, comprising: