JP4717774B2 - Injection molding machine - Google Patents

Description

  The present invention relates to an injection molding machine including a metering drive unit having a metering motor for rotating a screw and an injection drive unit having an injection motor for moving the screw back and forth.

  Conventionally, an in-line screw type injection molding machine equipped with an electric drive device for rotating and driving a screw is known in Japanese Patent Laid-Open No. 9-11290. This type of injection molding machine includes a metering drive unit having a metering motor for rotating the screw and an injection drive unit having an injection motor for moving the screw back and forth. In the metering process, the molding material is rotated by rotating the screw by the metering drive unit In the injection process, the screw is moved forward by the injection drive unit, whereby the measured resin is injected and filled into the mold.

On the other hand, a molding machine (injection molding machine) provided with an injection drive unit using a linear motor as an injection motor is known in Japanese Patent No. 3427171 because the injection drive unit performs an operation of moving the screw forward or backward. . This molding machine is a molding machine that includes a drive device that drives a screw to rotate and linearly move, and has a moving body portion that is movable in the axial direction and has a moving-side magnetic pole portion, and linearly moves the moving body portion. A linear motor unit comprising a fixed body part having a fixed side magnetic pole part to be provided, a moving side inclined surface is provided on the moving body part, a part of the moving side magnetic pole part is disposed on the moving side inclined surface, and the fixed body part A fixed-side inclined surface facing the moving-side inclined surface is provided on the fixed-side inclined surface, and a part of the fixed-side magnetic pole portion is arranged on the fixed-side inclined surface to form an injection driving unit, and the moving body unit is connected to the movable unit. The rotary motor part which rotates an output shaft is provided integrally, and the drive device which comprised the measurement drive part is provided.
JP-A-9-11290 Japanese Patent No. 3427171

  However, the conventional molding machine (injection molding machine) described above has the following problems to be solved.

  First, the injection process includes a filling area for speed control and a pressure holding area for pressure control. However, since it is not easy for a linear motor to intervene with a speed reduction mechanism (pressure increase mechanism), the screw is moved forward and backward. It is suitable for a filling region where movement, that is, speed control is performed, but is not suitable for a pressure holding region where pressure control is performed. For this reason, in the above-described conventional molding machine (Patent Document 2), the moving body portion is provided with a moving-side inclined surface, and a part of the moving-side magnetic pole portion is arranged on the moving-side inclined surface and moved to the fixed body portion. A fixed-side inclined surface facing the side-inclined surface is provided, and a part of the fixed-side magnetic pole portion is arranged on the fixed-side inclined surface to configure the injection driving unit. However, there is a limit to bear pressure control. In the end, in order to perform necessary and sufficient pressure control, the linear motor is considerably increased in size, but on the other hand, if the size is restricted, it is difficult to be versatile, such as being limited to a small molding machine with small capacity. There is.

  Secondly, since a geometric special structure is adopted in constructing the linear motor, a cost increase that cannot be ignored in terms of both component cost and manufacturing cost is caused. In addition, because it is based on a geometric configuration, the section where pressure can be increased is determined by the position of the moving body (screw) in the linear motor, and the setting and control of molding conditions corresponding to the shape and size of the molded product are flexible and flexible. In addition to being flexible, it cannot be easily adjusted during maintenance.

  An object of the present invention is to provide an injection molding machine that solves the problems existing in the background art.

  An injection molding machine M according to the present invention is provided with an injection drive unit Di having a measuring drive unit Dm having a measuring motor 3 for rotating the screw 2 and an injection motor moving the screw 2 forward and backward in order to solve the above-described problems. In the molding machine, a first injection motor 6 using a linear motor 6 s that moves the movable body 5 connected to the rear end of the screw 2 in the injection drive unit Di, a ball screw mechanism 8 that moves the movable body 5 back and forth, and A second injection motor 7 using a rotary motor 7s for rotating the rotation input portion 8i of the ball screw mechanism 8 is provided, and the first injection motor 6 and the second injection motor 7 are simultaneously or selectively driven and controlled. A control unit 9 is provided, and a cylindrical housing 11 is provided. On the inner peripheral surface of the housing 11, a fixed-side magnetic pole portion 12 of the linear motor 6s is disposed. 11, a movable body 5 having a moving-side magnetic pole portion 13 of the linear motor 6s disposed on the outer peripheral surface thereof is disposed so as to be movable back and forth, and a ball screw mechanism 8 is connected to a rear end surface of the movable body 5, and a housing 11 A rotary motor 7s is disposed at the rear end of the motor.

  In this case, according to a preferred aspect of the present invention, the cross-sectional shape perpendicular to the advance / retreat direction on the inner peripheral surface of the housing 11 and the cross-sectional shape perpendicular to the advance / retreat direction on the outer peripheral surface of the movable body 5 are formed in a circle. Alternatively, it may be formed in a polygon. Further, in the filling region Zif of the injection process Zi, the control unit 9 drives and controls at least the first injection motor 6 to advance the screw 2, and the second injection in a partial section Zfp from the start of advancement of the screw 2. The motor 7 can be driven and controlled simultaneously with respect to the first injection motor 6, and at least the second injection motor 7 is driven and controlled to hold pressure on the screw 2 in the pressure holding area Zih of the injection process Zi. At the same time, the first injection motor 6 can be simultaneously driven and controlled with respect to the second injection motor 7 in the partial zone Zhp during the holding pressure.

  According to the injection molding machine M according to the present invention having such a configuration and technique, the following remarkable effects can be obtained.

  (1) The injection drive unit Di is constituted by the first injection motor 6 using the linear motor 6s and the second injection motor 7 using the rotary motor 7s, and the first injection motor 6 and the second injection motor 7 are simultaneously used. Alternatively, since the controller 9 that selectively controls the drive is provided, necessary and sufficient pressure control can be performed in the injection process Zi, and the linear motor 6s can be downsized or an injection molding machine having a large capacity can be put into practical use. Can be realized.

  (2) The first injection motor 6 using the linear motor 6s and the second injection motor 7 using the rotary motor 7s are combined, and the first injection motor 6 and the second injection motor 7 are simultaneously or selectively driven and controlled. Therefore, the general-purpose linear motor 6s and the general-purpose rotary motor 7s can be used, and the cost can be reduced in both the component cost and the manufacturing cost. Further, setting and control of molding conditions corresponding to the shape and size of the molded product can be performed flexibly and flexibly, and adjustment during maintenance can be easily performed.

  (3) The injection drive unit Di has a fixed-side magnetic pole portion 12 of the linear motor 6s disposed on the inner peripheral surface of the cylindrical housing 11, and a moving-side magnetic pole of the linear motor 6s on the outer peripheral surface inside the housing 11. Since the movable body 5 provided with the portion 13 is disposed so as to be movable back and forth, the ball screw mechanism 8 is connected to the rear end surface of the movable body 5, and the rotary motor 7s is disposed at the rear end of the housing 11, A rational combination of the linear motor 6s and the rotary motor 7s can contribute to further miniaturization and compactness.

  (4) According to a preferred embodiment, the cross-sectional shape perpendicular to the advancing / retreating direction on the inner peripheral surface of the housing 11 and the cross-sectional shape perpendicular to the advancing / retreating direction on the outer peripheral surface of the movable body 5 can be formed in a circular or polygonal shape. The shapes of the housing 11 and the movable body 5 can be arbitrarily selected according to the use and purpose, and a high degree of flexibility in design can be ensured.

  (5) According to a preferred embodiment, at least the first injection motor 6 is driven and controlled to advance the screw 2 in the filling region Zif of the injection process Zi, and a part from the start of advancement of the screw 2 is caused. If the function of simultaneously driving and controlling the second injection motor 7 with respect to the first injection motor 6 in the section Zfp is provided, the forward movement of the screw 2 is shared by the first injection motor 6 (linear motor 6s) and a large torque is generated. Since the second injection motor 7 (rotary motor 7s) is added in a partial section Zfp from the start of advancement of the screw 2 that is required, an optimal control mode in the filling region Zif can be realized.

  (6) According to a preferred embodiment, at least in the pressure holding region Zih of the injection process Zi, the controller 9 controls the drive of the second injection motor 7 to apply the holding pressure to the screw 2 and also applies the holding pressure. If the function of simultaneously driving and controlling the first injection motor 6 with respect to the second injection motor 7 is provided in the partial zone Zhp, the holding pressure for the screw 2 is shared by the second injection motor 7 (rotary motor 7s). In order to add the first injection motor 6 (linear motor 6s) in the partial zone Zhp during holding pressure, which is a high pressure addition zone when performing multistage control of pressure, an optimal control mode in the holding pressure zone Zih is realized. Can do.

  Next, the best embodiment according to the present invention will be given and described in detail with reference to the drawings.

  First, the configuration of an injection molding machine M according to this embodiment will be described with reference to FIGS. 1 and 2.

  FIG. 1 shows an injection device Mi in an inline screw type injection molding machine M. The injection device Mi includes a heating cylinder 31 having an injection nozzle 32 at the tip and a hopper 33 at the rear, and the rear end of the heating cylinder 31 is installed on the machine base Mb via a support plate 34. Further, the heating cylinder 31 incorporates the screw 2 so as to be rotatable and advanceable / retractable, and the screw 2 is driven to rotate or advance / retreat by a driving device 35 disposed behind the support plate 34. The driving device 35 is installed on the machine base Mb via the support board 36.

  The drive device 35 includes a metering drive unit Dm having a metering motor 3 for rotating the screw 2 and an injection drive unit Di having injection motors 6 and 7 for moving the screw 2 forward and backward. The injection drive unit Di includes a first injection motor 6 using a linear motor 6s that moves the movable body 5 connected to the rear end of the screw 2 forward and backward, a ball screw mechanism 8 that moves the movable body 5 forward and backward, and the ball screw mechanism. And a second injection motor 7 using a rotary motor 7s for rotating the eight rotation input portions 8i.

  In this case, the driving device 35 includes a cylindrical housing 11 integrally having a rear end wall portion 11r at a rear end portion and an open front end portion, and accommodates the movable body 5 inside the housing 11. . The cross-sectional shape perpendicular to the advancing / retreating direction on the inner peripheral surface of the housing 11 and the cross-sectional shape perpendicular to the advancing / retreating direction on the outer peripheral surface of the movable body 5 are circular as shown in FIG. Then, the outer peripheral portion of the coupling 15 fixed to the rear end of the screw 2 and the concave coupling portion 5 f provided at the front end portion of the movable body 5 are rotatably coupled via a bearing 16. The bearing 16 is provided with a load cell (not shown) that detects the pressure applied to the screw 2.

  The illustrated linear motor 6s is a moving magnet type linear motor. Therefore, the coil 12c that becomes the fixed-side magnetic pole portion 12 of the linear motor 6s is attached to the inner peripheral surface of the housing 11, and the magnet 13m that becomes the moving-side magnetic pole portion 13 of the linear motor 6s is attached to the outer peripheral surface of the movable body 5. Install ... Since this linear motor 6s employs a three-phase alternating current drive system, a plurality of slots formed on the inner peripheral surface of the housing 11 using a magnetic material correspond to three phases (U phase, V phase, W phase). A plurality of coils 12c... Are sequentially arranged in the axial direction (advancing and retreating direction of the movable body 5) with an electrical angle shifted by 120 °, and a plurality of coils 12c. Of magnets 13m are arranged.

  On the other hand, the rotary motor 7s is attached to the outer surface of the rear end wall portion 11r of the housing 11. The screw shaft 8s of the ball screw mechanism 8 is coupled to the rotary shaft 17 of the rotary motor 7s, and the nut 5 is coupled to the concave coupling portion 5r provided at the rear end of the movable body 5. The outer peripheral portion of the nut portion 8 n in the ball screw mechanism 8 is fixed through the holding portion 18. In this case, an allowable space 5p through which the screw portion 8s is inserted is provided inside the movable body 5. A three-phase AC drive type servo motor can be used as the rotary motor 7s. A guide restricting portion 19 is provided between the rear end of the movable body 5 and the rear end wall portion 11r of the housing 11 to restrict the rotation of the movable body 5 and allow the movable body 5 to move forward and backward. The guide restricting portion 19 can be constituted by, for example, a plurality of guide pins 20 projecting axially rearward from the rear end of the movable body 5 and a collar member 21 slidably supporting the guide pins 20. Reference numeral 22 denotes a protective cover that covers the rotary motor 7s. Thus, the injection driving unit Di having the first injection motor 6 using the linear motor 6s and the second injection motor 7 using the rotary motor 7s is configured.

  Further, a weighing motor support 23 that protrudes forward is integrally formed on the front end surface of the movable body 5, and the weighing motor 3 that constitutes the weighing drive unit Dm via the support base 24 is formed on the weighing motor support 23. Install. This measuring motor 3 is a rotary motor, and a three-phase AC drive type servo motor can be used. The rotation of the metering motor 3 is transmitted to the screw 2 via the rotation transmission mechanism 25. In this case, the rotation transmission mechanism 25 spans between a driven pulley attached to a predetermined position on the outer peripheral surface of the rear portion of the screw 2, a driving pulley attached to the rotating shaft of the metering motor 3, and between the driven pulley and the driving pulley. An endless rotation transmission belt (timing belt) is provided.

  The linear motor 6s (first injection motor 6), rotary motor 7s (second injection motor 7), and metering motor 3 described above are added to the control unit 9 having a computer function for performing various controls and processes in the injection molding machine M. Connecting. Thereby, each motor 6s, 7s, 3 is driven and controlled by the controller 9, and in particular, at least the linear motor 6s and the rotary motor 7s are driven or controlled simultaneously or selectively according to the present invention. Therefore, the control unit 9 incorporates an inverter that generates a control pattern for driving and controlling the linear motor 6s, the rotary motor 7s, and the metering motor 3. Reference numeral 51 denotes a rotary encoder that detects the rotation of the rotary motor 7s, 52 denotes a rotary encoder that detects the rotation of the metering motor 3, and 53 denotes a setting unit connected to the control unit 9. Various settings can be made.

  Next, operation | movement of the injection molding machine M which concerns on this embodiment is demonstrated according to the flowchart shown in FIG. 4, referring each figure.

  First, as shown in FIG. 3, in the injection process Zi, a filling region (filling process) Zif is first performed. Since the filling area Zif is a speed control area in which the screw 2 is moved forward, a linear motor 6s suitable for speed control is basically used. In this case, in order to advance the stopped screw 2 in the initial stage of the filling area Zif, a large torque for accelerating the screw 2 is required. In the initial stage of the filling area Zif, the rotary motor 7s is operated simultaneously. That is, as shown in FIG. 3, the rotary motor 7s is simultaneously operated in addition to the operation of the linear motor 6s until the partial section Zfp with a predetermined set time elapses from the start of the filling region Zif. 2 is supported (steps S1 and S2). The set time for the partial section Zfp is preferably set to a time for at least the screw 2 to reach a steady speed. Accordingly, at this time, axial thrust is applied to the movable body 5 by the linear motor 6s, and at the same time, the rotation of the rotary motor 7s is converted into thrust in the straight traveling direction by the ball screw mechanism 8 and the movable body. 5 is added.

  When the set time (partial section Zfp) has elapsed, the rotary motor 7s is stopped (steps S3 and S4). Thereby, after this, the filling region Zif by the speed control of only the linear motor 6s is performed. Thus, since the linear motor 6s and the rotary motor 7s are simultaneously driven and controlled until the set time (partial section Zfp) elapses from the start of the advancement of the screw 2, a sufficient torque for accelerating the screw 2 can be easily secured. And an optimal control mode in the filling region Zif can be realized.

  On the other hand, when the filling area Zif approaches the end and reaches the set time immediately before filling ti, as shown in FIG. 3, brake control is performed to energize the linear motor 6s in the reverse direction (steps S5 and S6). . Thereafter, when the set filling end time to elapses, the linear motor 6s is stopped (steps S7 and S8). Thus, the filling area Zif ends.

  Next, the process proceeds to a pressure holding region (pressure holding step) Zih. Since the pressure holding area Zih is a pressure control area in which the screw 2 is almost stopped, a rotary motor 7s suitable for pressure control is basically used. In this case, the linear motor 6s is simultaneously operated in the high pressure stage when performing the multistage control, and only the rotary motor 7s is operated in the low pressure stage. That is, as shown in FIG. 3, first, the rotary motor 7s is actuated by the start of the pressure holding area Zih to perform pressure control by the first low pressure stage (step S9). When the first-stage pressure control is completed and the preset high-pressure start time ts is reached, the linear motor 6s is simultaneously operated in addition to the rotary motor 7s, and the pressure control by the second-stage high-pressure stage is performed ( Steps S10 and S11). As described above, since the linear motor 6s and the rotary motor 7s are simultaneously driven and controlled in the partial section Zhp during the holding pressure application, the high holding pressure applied to the screw 2 can be easily secured, and the optimum in the holding pressure area Zih. Control mode can be realized.

  When the second-stage pressure control is finished and the preset high pressure end time te is reached, the linear motor 6s is stopped (steps S12 and S13). Thus, thereafter, pressure control only for the rotary motor 7s, that is, pressure control by the third low pressure stage is performed by operating only the rotary motor 7s (step S9). When the set pressure holding end time tx is reached, the rotary motor 7s is stopped (steps S14 and S15). Thus, the pressure holding area Zih and the injection process Zi are completed.

  Thereafter, when the next shot (molding) continues, the process proceeds to the weighing process Zm for the next shot (step S16). In the weighing process Zm, the weighing motor 3 is driven and controlled to perform weighing (step S17). At this time, a back pressure is applied to the screw 2. Since the back pressure at this time is sufficient, a back pressure is applied by controlling the linear motor 6s. In the weighing process Zm, the rotation of the weighing motor 3 is transmitted to the screw 2 via the rotation transmission mechanism 25. And if the measurement process Zm is complete | finished, the injection process Zi mentioned above will be performed similarly (step S1 ...).

  Thus, according to the injection molding machine M according to the present embodiment, the injection driving unit Di is configured by the first injection motor 6 using the linear motor 6s and the second injection motor 7 using the rotary motor 7s. In addition, since the controller 9 that controls the first injection motor 6 and the second injection motor 7 simultaneously or selectively is provided, necessary and sufficient pressure control in the injection process Zi can be performed, and the linear motor 6s. This makes it possible to achieve downsizing or practical use of an injection molding machine having a large capacity. Further, the first injection motor 6 using the linear motor 6s and the second injection motor 7 using the rotary motor 7s are combined, and the first injection motor 6 and the second injection motor 7 are simultaneously or selectively driven and controlled. Therefore, the general-purpose linear motor 6s and the general-purpose rotary motor 7s can be used, and the cost can be reduced in both the component cost and the manufacturing cost. Further, setting and control of molding conditions corresponding to the shape and size of the molded product can be performed flexibly and flexibly, and adjustment during maintenance can be easily performed. In addition, the injection drive unit Di has a fixed-side magnetic pole portion 12 of the linear motor 6s disposed on the inner peripheral surface of the cylindrical housing 11, and a moving-side magnetic pole portion of the linear motor 6s on the outer peripheral surface inside the housing 11. Since the movable body 5 provided with 13 is disposed so as to be movable back and forth, the ball screw mechanism 8 is connected to the rear end face of the movable body 5, and the rotary motor 7 s is disposed at the rear end of the housing 11. The rational combination of the motor 6s and the rotary motor 7s can contribute to further miniaturization and compactness.

  Although the best embodiment has been described in detail above, the present invention is not limited to such an embodiment, and the scope of the present invention is not deviated from the gist of the present invention in terms of the detailed configuration, shape, quantity, technique, and the like. It can be changed, added, or deleted arbitrarily.

  For example, in FIGS. 1 and 2, a cross-sectional shape perpendicular to the advancing / retreating direction on the inner peripheral surface of the housing 11 and a cross-sectional shape perpendicular to the advancing / retreating direction on the outer peripheral surface of the movable body 5 are formed in a circle. Although the case has been illustrated, it is also possible to form a polygon as shown in FIGS. 5 and 6, that is, a quadrangle as shown in FIG. 5 or a hexagon as shown in FIG. In addition, the moving magnet type linear motor is exemplified as the linear motor 6s, but it may be a moving coil type linear motor or a configuration (partial configuration) of the linear motor employed in the above-mentioned Japanese Patent No. 3427171. It doesn't matter. 5 and 6, the same parts as those in FIG. 2 are denoted by the same reference numerals to clarify the configuration, and detailed description thereof is omitted. Furthermore, in the exemplary embodiment, the case where the rotary motor 7s and the screw portion 8s in the ball screw mechanism 8 are directly coupled is shown, but the rotation may be transmitted by a rotation transmission mechanism using a pulley and a belt. The mounting position of the rotary motor 7s can be arbitrarily changed. Further, the ball screw mechanism 8 may be configured to fix the screw 8s and rotate the nut portion 8n, and the mounting of the metering motor 3 and the rotation transmission mechanism are not limited to the examples, and any configuration can be adopted. . On the other hand, the control pattern (control mode) for driving the linear motor 6s (first injection motor 6) and the rotary motor 7s (second injection motor 7) simultaneously or selectively is not limited to the example (FIG. 3). Arbitrary control patterns can be set according to the application.

Sectional side view showing an injection device in an inline screw type injection molding machine according to the best embodiment of the present invention, Sectional front view including a ball screw mechanism in the same injection molding machine, A timing chart showing the operation of each motor in the same injection molding machine; A flowchart for explaining the operation of the injection molding machine; Sectional front view including a ball screw mechanism in an injection molding machine according to a modified embodiment of the present invention, Sectional front view including a ball screw mechanism in an injection molding machine according to another modified embodiment of the present invention,

  2: screw, 3: metering motor, 5: movable body, 6: first injection motor, 6s: linear motor, 7: second injection motor, 7s: rotary motor, 8: ball screw mechanism, 8i: rotation input unit, 9: Controller, 11: Housing, 12: Fixed magnetic pole, 13: Moving magnetic pole, M: Injection molding machine, Dm: Metering drive, Di: Injection drive, Zi: Injection process, Zif: Filling area , Zih: pressure holding region, Zfp: partial section, Zhp: partial section

Claims (5)

  In an injection molding machine comprising a metering drive unit having a metering motor for rotating a screw and an injection drive unit having an injection motor for moving the screw back and forth, a movable body connected to the rear end of the screw is moved forward and backward. A first injection motor using a linear motor, a ball screw mechanism for moving the movable body forward and backward, and a second injection motor using a rotary motor for rotating a rotation input portion of the ball screw mechanism, and The controller includes a control unit that controls drive control of the first injection motor and the second injection motor simultaneously or selectively, and has a cylindrical housing, and a fixed-side magnetic pole portion of the linear motor is provided on an inner peripheral surface of the housing. In the housing, the movable body in which the moving-side magnetic pole portion of the linear motor is disposed on the outer peripheral surface is disposed so as to be movable back and forth. With connecting the ball screw mechanism in the rear end surface of the movable body, an injection molding machine, characterized in that formed by disposing the rotary motor to the rear end of the housing.   A cross-sectional shape perpendicular to the advance / retreat direction on the inner peripheral surface of the housing and a cross-sectional shape perpendicular to the advance / retreat direction on the outer peripheral surface of the movable body are formed in a circular shape. The injection molding machine according to claim 1.   The cross-sectional shape perpendicular to the advancing / retreating direction on the inner peripheral surface of the housing and the cross-sectional shape perpendicular to the advancing / retreating direction on the outer peripheral surface of the movable body are formed into polygons. The injection molding machine according to claim 1.   The control unit drives and controls the first injection motor at least in the filling region of the injection process to advance the screw, and sets the second injection motor in a partial section from the start of advancement of the screw. 2. The injection molding machine according to claim 1, wherein the first injection motor is simultaneously driven and controlled.   In the pressure holding region of the injection process, the control unit drives and controls at least the second injection motor to apply a holding pressure to the screw, and the first injection motor in a partial section during the holding of the pressure. 5. The injection molding machine according to claim 1, wherein drive control is performed simultaneously with respect to the second injection motor.

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