JP2005081633A - Motor-driven injection molding machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a miniaturized electromotive injection molding machine simple as a whole. <P>SOLUTION: In this electromotive injection molding machine 1, a fixed mold 11 and a clamped movable mold 12 are attached to a movable template 13 and two ball screws 17 and 18 for moving the movable template 13 are passed through the movable template 13 at two points on the diagonal thereof and the groove parts of the ball screws 17 and 18 are set to a cantilevered state and rotated through pulleys 55 and 55 and a timing belt 56 to move the movable template 13. Further, the movable template 13 is guided by a slide guide having a structure that the bearing units 14 fixed to the lower part of the movable template 13 itself on both sides thereof are fitted to linear rails 15 and 16. On the other hand, two tie bars 35 and 36 and two ball screws 37 and 38 on the diagonal of the movable template 13 on an injection side and the movable plate 33 on the injection side to which an injection plunger 42 is fixed by the slide guide are moved. The movable template 13 is moved by the ball screws 17 and 18 on an on-off side to clamp both molds and the movable plate 33 on the injection side is subsequently moved to perform injection. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an electric injection molding apparatus in which opening and closing of a mold, injection of molten material, and removal of a molded product are driven by an electric motor.

  Generally, an injection molding machine is composed of a mold opening / closing mechanism that opens and closes a mold and clamps the mold, an injection mechanism that melts and injects pellets of the molding material, and a drive mechanism that automatically moves these. The The mold opening / closing mechanism is a mechanism that clamps the mold by clamping the mold with high pressure. The mold clamping mode is a toggle type that opens and closes the mold by the toggle mechanism and a hydraulic cylinder directly. It is roughly divided into a direct pressure type that performs mold clamping.

  By the way, the toggle type electric injection molding apparatus can generate a high molding pressure by the toggle mechanism. However, since the mechanism requires a large space, the toggle type molding apparatus is often large. On the other hand, the direct pressure injection molding apparatus 400 using the hydraulic cylinder 401 shown in FIG. 11A is also large due to the space for installing the hydraulic cylinder 401. Also, in the direct pressure type apparatus, an electric injection molding apparatus 300 having a configuration in which the hydraulic cylinder 401 is replaced with a ball screw 301 as shown in FIG. However, the direct pressure electric injection molding apparatus 300 using the ball screw 301 has the following drawbacks. In FIG. 11, reference numerals 305 and 402 denote frame support stands.

  Normally, the die plate 302 provided for opening and closing the mold is provided with four tie bars 303 (two are hidden and cannot be seen), and the die plate 302 is moved to the tie bar 303 by the push of the ball screw 301. The mold 304 can be opened and closed. And in the structure using such a ball screw 301, since the space S for making the ball screw 301 protrude from an opening-closing mechanism or an injection mechanism is required, the apparatus was enlarged.

  An object of the present invention is to provide an electric injection molding apparatus capable of reducing the overall weight of the electric injection molding apparatus.

Means for Solving the Problems and Effects of the Invention

In order to solve the above problems, the electric injection molding machine of the present invention is
A central fixed plate that supports the fixed mold of the mold;
A movable plate that is arranged so as to be movable toward and away from the central fixed plate and supports the movable mold of the mold;
A slide guide that receives the lower part of the movable plate and guides the movable plate so as to be slidable in the approaching / separating direction;
A ball screw extending in a cantilevered state from the central fixed plate toward the movable mold plate, for example, two ball screws for opening and closing a mold that are screwed to the movable mold plate at two diagonal points;
An electric motor for opening and closing the mold that rotates the ball screw in the cantilever state in both forward and reverse directions to move the movable mold plate closer to and away from the center fixed plate;
The fixed mold and the movable mold are arranged on the opposite side of the movable mold plate with respect to the central fixed plate so as to face the mold opening / closing mechanism configured as described above, and the fixed mold and the movable mold are moved by the approach of the fixed mold plate and the movable mold plate. An injection mechanism including an injection electric motor that pushes the molten resin into the mold in the mold clamping state;
It is characterized by including.

  As described above, the number of parts is reduced by eliminating the conventional tie bar (guide bar) by guiding the movable plate with a slide guide that supports the movable plate at the bottom, and there is no need for a portion to pass the tie bar through the movable plate. Since only an appropriate number of, for example, two diagonal ball screws pass through the movable plate, the movable plate can be made small, and the structure of the plate is simplified.

  Further, by supporting, for example, two ball screws penetrating the movable plate in a cantilever state, an end plate for supporting the end portion of the ball screw becomes unnecessary. This further reduces the number of parts and eliminates the end plate, thereby simplifying the structure and reducing the size of the apparatus because no space is required for arranging the end plate. Therefore, the cantilevered ball screw is rotationally driven via a pulley or the like in order to move the movable mold plate, so that the movable mold plate can be opened and closed without any inconvenience. In addition, although the ball screw is in a cantilever state, since it is screwed with the movable plate, it is received by the movable plate, the ball screw moves the movable plate, and the movable plate is in the cantilever state of the ball screw. As a result, the device is simplified and miniaturized in cooperation.

  And, as described above, the tie bar that guides the ball screw is abolished, the end plate is abolished with the ball screw in a cantilever state, the number of parts is reduced, the device configuration is synergistically simplified, and miniaturization is also achieved. Is done. As a result, the installation area is reduced, and the number of electric injection molding apparatuses that can be installed in a certain space can be increased.

  Next, in the electric injection molding apparatus configured as described above, in the mold clamping operation of the opening / closing mechanism, the mold clamping stroke can be detected based on the change in the load current value of the electric motor dedicated to the opening / closing mechanism. In this case, since the sensor for detecting the position of the movable mold plate or the like is not used, it is possible to save the trouble of re-aligning the sensor even when the mold thickness changes.

  On the other hand, the injection amount in the injection mechanism can be controlled based on a signal from a sensor that detects the filling state of the molding material into the molding cavity of the mold. In this case, a sensor can be provided in the mold to detect the filling amount of the molding material, and an appropriate injection amount can be controlled by the signal. This eliminates the need to use two sensors, i.e., a sensor that detects the amount of movement of the plunger or the like, and a sensor that detects the injection pressure, as in the prior art, thereby reducing costs.

    Furthermore, in the injection mechanism, a screw for kneading the molding material that can rotate in a fixed position in the axial direction in the injection cylinder, and receiving the kneaded molding material penetrating on the central axis of the screw A plunger-in screw including a hole and a plunger that is inserted through the receiving hole and injects the kneaded material to be molded may be provided. In this case, the screw melts to a temperature suitable for molding while quickly kneading the molding material, and then the plunger injects the kneaded molding material into a mold at an appropriate pressure. Therefore, the injection process can be performed quickly and efficiently, and the injection mechanism can be downsized as compared with a normal screw type.

  Further, two sets of injection mechanisms are provided so that they can be injected separately. In the mold opening / closing mechanism, two fixed molds are attached to the central fixed plate, and one movable mold is attached to the open / close movable plate as a slide mechanism. Thus, it is configured to be slidable in a direction perpendicular to the moving direction of the movable plate at positions where the two fixed molds are respectively fitted, and two-color molding can be performed by this configuration. That is, by attaching two fixed molds to the central fixed plate and having the above configuration, the two-color molding can be performed also in the electric injection molding apparatus of the present invention using the rotation of the ball screw as the opening / closing mechanism. A ball screw or the like similar to that of the movable plate can be used as the slide mechanism of the movable mold.

In the combination of the two injection mechanisms described above, the two sets are the primary side and the secondary side, and depending on the molding material used, are both the primary side and the secondary side in two-color molding a plunger type? Either one of the primary side and the secondary side is a plunger type and the other is a plunger in screw type, or both the primary side and the secondary side are plunger in screw types, can do.
The injection method is divided into a plunger direction or a screw direction depending on the material to be molded or the shape of the target molded body. The plunger type has many staying portions during injection and has a large injection pressure loss, so that it is difficult to inject a material with poor thermal stability.
Therefore, when two-color molding is performed, by combining the plunger type and the plunger-in-screw type with the molding material used as described above, the molding material can be efficiently injected without stagnation.

  Hereinafter, embodiments of the present invention will be described based on examples shown in the drawings.

  An electric injection molding apparatus 1 (hereinafter also simply referred to as an apparatus) shown in FIG. 1 according to an embodiment of the present invention is provided with a frame 2 serving as a base of the apparatus 1 and a center of the apparatus 1. 2 and a mold opening / closing mechanism section 10 and an injection mechanism section 30 that are separated from each other with the center fixing plate 3 as a boundary. Also, drive mechanisms 50 and 50 for driving the mold opening / closing mechanism 10 and the injection mechanism 30 are provided in or around the frame 2.

  The mold opening / closing mechanism unit 10 is provided with a central fixed plate 3 and an open / close side movable plate 13 (movable mold plate) disposed so as to be able to approach and separate from the central fixed plate 3. Opening and closing side ball screws 17 and 18 are inserted into the movable plate 13 diagonally. As shown in FIG. 2, the ball screw nut 21 provided on the movable plate 13 includes a screw portion of the open / close side ball screw 18 (the other ball screw 17 is also explained by taking 18 as an example). It is the structure inserted in by screwing.

  The open / close side ball screw 18 can be rotated by an open / close side motor 51 shown in FIG. 1 via a timing belt 56 and pulleys 55, 55 as transmission members, and the ball screw 18 is attached to the central fixing plate 3. It is inserted through a bearing 22 (FIG. 2). The open / close side ball screw 17 has the same configuration. Both the ball screws 17 and 18 rotate in the same direction in synchronization with each other by driving the motor 51 via the timing belt 56 and the pulleys 55 and 55, whereby the movable plate 13 moves relative to the central fixed plate 3.

A movable mold plate (open / close side movable plate) 13 on the mold opening / closing mechanism 10 side is guided by a slide guide so as to be slidable in a direction approaching and separating from the central fixed plate 3. The slide guide includes two linear rails 15 and 16 which are laid on the upper surface of the frame 2 along the moving direction of the movable plate 13 and parallel to each other, and a bearing unit 14 fixed to both lower sides of the movable plate 13. , 14, and each bearing unit 14 is fitted to the linear rails 15, 16 and moves on the rails.

  As shown in FIG. 3, each bearing unit 14 rolls around the upper ball groove corresponding to both sides of each rail 15 or 16, and rolls around the lower ball groove. Balls 27 and 27 and ball holders 28 and 28 for holding these balls 26 and 27 are provided, and the load of the movable plate 13 is received by the rails 15 and 16 through the balls 26 and 27, respectively. As the ball 13 moves on the rails 15 and 16, the balls 26 and 27 roll to reduce friction.

  As shown in FIG. 1, the ends of the ball screws 17 and 18 projecting outward from the movable plate 13 (opposite to the central fixed plate 3) are not supported by the end plate, but are cantilevered and driven. The result is that the movable plate 13 is supported by being screwed. The pulleys 55 are attached to the end portions of the ball screws 17 and 18 in a cantilever state, and the timing belt 56 driven by the motor 51 is stretched over the pulleys 55 and 55 to rotate in the cantilever state. The two ball screws 17 and 18 to be moved move the movable plate 13. Each of the ball screws 17 and 18 passes through two diagonal points of the movable plate 13 so that the driving force of the ball screws 17 and 18 is applied to the movable plate 13 as evenly as possible. The motor 51 described above is an electric motor for opening and closing the mold that rotates the ball screws 17 and 18 in a cantilever state in both forward and reverse directions to move the movable mold plate 13 toward and away from the central fixed plate 3.

  Since there is no tie bar (guide bar) for guiding the movable plate 13, the movable plate 13 does not require a guided portion (such as a through hole) for the tie bar, and the shape of the movable plate 13 can be reduced. . For example, as shown in FIG. 3, it can be set as the compact form which deleted the part (for example, upper right part of the plate 13) which the tie bar penetrated conventionally. The absence of a guide bar eliminates the need for an end plate to support the end of the bar. The ball screws 17 and 18 exist, but the end plate supporting the end of the ball screw is eliminated, and the ball screw is driven in a cantilever state, thereby eliminating the end plate and the guide bar. An electric injection molding device is realized.

  A movable mold 12 is assembled to the movable mold plate 13, and a fixed mold 11 is assembled to the center fixed plate 3. The movable mold 12 moves together with the movable mold plate 13, and the molds 11 and 12 are clamped by the approach thereof, and the mold opening is performed by separation.

As shown in FIG. 1, the injection mechanism unit 30 is arranged between the central fixed plate 3, the injection side fixed plate 34, and the injection side that is arranged between the central fixed plate 3 and the injection side fixed plate 34 and is movable in the axial direction. And a movable plate 33. Further, two injection-side tie bars 35 and 36 and two injection-side ball screws 37 and 38 are inserted diagonally into the injection-side movable plate 33. The injection-side movable plate 33 is configured to move in the axial direction when the injection-side ball screws 37 and 38 are rotated by the injection-side motor 52 via the pulleys 57 and 57 and the timing belt 56.
The ejection side movable plate 33 can be guided with respect to the frame 2 by the slide guides shown in FIGS. 1 and 3, that is, the rails 15 and 16 and the bearing units 14 and 14 assembled thereto. .

  A plunger 42 for injecting a molding material (resin) is fixed on the central axis of the injection side movable plate 33, and a cylinder 41 coaxial with the plunger 42 and capable of receiving the plunger 42 is injected. The mechanism 30 is provided substantially at the center. That is, the injection mechanism 30 of the electric injection molding apparatus 1 is configured as a plunger type. Above the cylinder 41, a hopper 43 for feeding the molding material into the injection mechanism section 30 is provided. Further, on the outer peripheral portion of the cylinder 41, a melt capable of injecting the molding material by heating. A heater 40 is provided. The plunger 42 is configured to repeat the reciprocating motion as the ejection side movable plate 33 moves in the axial direction.

  Here, the molten material is injected from the injection mechanism 30 to the mold opening / closing mechanism 10 via the central fixed plate 3.

  The drive mechanism units 50 and 50 at both ends of the apparatus 1 include an opening / closing side motor 51 for driving the opening / closing side ball screws 17 and 18 of the opening / closing mechanism unit 10 and the injection side ball screws 37 and 38 of the injection mechanism unit 30. An ejection side motor 52 for driving is housed inside the frame 2.

  The open / close motor 51 has a built-in sensor for detecting the load current value of the drive. This is for controlling the stroke of clamping in the opening / closing mechanism, and when the load current value of the motor 51 corresponding to the clamping pressure is set, a predetermined load current value is reached. Then, the driving of the motor 51 is stopped, and an injection preparation state is set.

  As shown in FIG. 4, the ejector plate 83 in the movable mold 12 is provided with a sensor 70 that detects the filling amount of the molding material W injected by the plunger 42. 4A, since the molding material W is not filled, the tip 73 of the molded product protruding pin 85 is urged by the web spring 72 formed on the end surface of the sensor 70. It protrudes slightly into the cavity 74. Next, when the molding material W is injected by the plunger 42 and filled into the cavity 74 as shown in FIG. 4B, the molded product protruding pin 85 moves slightly due to the pressure of the molding material W, and the web The spring 72 is elastically deformed into a substantially flat plate shape and comes into contact with the sensor 70. The injection amount is controlled by the injection-side motor 52 (FIG. 1) based on the signal of the sensor 70 that is in contact therewith.

  A molding mechanism from mold clamping to injection of the electric injection molding apparatus 1 configured as described above will be described with reference to FIG. FIG. 5 is a simplified diagram showing two ball screws with the tie bar on the injection mechanism side omitted for easy understanding.

  First, in the electric injection molding apparatus 1 in the standby state shown in FIG. 5D, the ball screws 17 and 18 are rotated by the operation of the open / close side motor 51, thereby moving the movable plate 13 toward the center fixed plate 3. As the movable mold plate 13 moves, the movable mold 12 enters a mold clamping state shown in FIG. The completion of the mold clamping is detected when the load current value of the open / close motor 51 reaches a predetermined set value. Subsequently, in this state, the operation of the injection side motor 52 causes the ball screws 37 and 38 to rotate, whereby the injection side movable plate 33 moves toward the central fixed plate 3, and the plunger 42 similarly has the central fixed plate 3. By moving to the side, the injection state shown in FIG.

  Here, the injection-side movable plate 33 is placed on the side of the central fixed plate 3 until the filling of the molding material into the cavity 74 (FIG. 4) is completed by the sensor 70 (FIG. 4) provided on the movable mold 12. To complete the injection.

  When the sensor 70 sends a signal indicating that the filling is completed to the injection side motor 52, the injection side motor 52 reverses its drive, and the plunger 42 together with the injection side movable plate 33, as shown in FIG. It moves to the injection side fixed plate 34 side and enters a standby state. On the other hand, the opening / closing side motor 51 also reverses when a certain holding time after injection elapses, and the movable mold 12 moves in the opening direction together with the movable mold plate 13, and the mold opening state shown in FIG.

  Here, although not shown in FIG. 5, the molded product A is released from the cavity by the operation of a predetermined air cylinder, and the molded product is recovered from the recovery unit 60.

  Next, a modification of the electric injection molding apparatus 1 is shown in FIG. In addition, the same code | symbol is attached | subjected to the same structure and mechanism as the electric injection molding apparatus 1, and description is abbreviate | omitted. The injection mechanism unit 130 of the electric injection molding apparatus 100 forms a screw 145 for kneading a material to be molded in a cylinder 141. On the central axis of the screw 145, a receiving hole 146 for storing the kneaded material to be kneaded is formed, and the plunger 142 slides in a state allowing the rotation of the screw 145 in the receiving hole 146. The plunger-in-screw type injection mechanism 130 is configured to be fitted. The screw 145 is driven by a motor 53 provided inside the frame 2.

  The material to be molded introduced from the hopper 43 by the electric injection molding apparatus 100 having the above configuration is melted by the heater 140 while being kneaded by the screw 145 in the cylinder 141, so that the material is uniformly and efficiently melted. Further, the melted material (resin) is stored in the receiving hole 146 formed at the front end of the screw 145 while retracting the plunger 142, and the molten resin in the receiving hole 146 is injected into the mold by the advancement of the plunger 142. It has become so. In this way, in the plunger-in-screw type in which the screw 145 rotates at a fixed position and the plunger 142 moves forward in the screw 145, the plunger 142 moves forward / backward through the injection-side movable plate 33 described above.

  FIG. 7 shows a so-called two-color electric injection molding apparatus 200 including two sets of the injection mechanism 30 of the electric injection molding apparatus 1 of FIG. In addition, about the thing of the same structure and mechanism as the electric injection molding apparatus 1, the same code | symbol is attached | subjected and description is abbreviate | omitted. In the opening / closing mechanism 290 of the apparatus 200, two fixed molds for two colors, that is, a primary side fixed mold 220 and a secondary side fixed mold 221 are attached to the central fixed plate 3. On the other hand, one movable mold 210 is attached to the movable mold plate 13, and the movable mold 210 is moved by a mold moving ball screw 213 arranged in a direction perpendicular to the moving direction (axial direction) of the movable plate 13. It is possible to slide in that direction, and the mold can be clamped to the two fixed molds 220 and 221 by this slide.

  The mold moving ball screw 213 is rotated by a motor dedicated to the mold moving ball screw (not shown) via the mold moving pulley 212, and the movable mold 210 has a first position facing the primary fixed mold 220. It moves between the second position facing the secondary fixed mold 221.

  On the other hand, in the injection mechanism section 280, the primary side injection unit 230 that injects a molding material (molten resin) to the primary side fixed mold 220 and the molding material 2 to the secondary side fixed mold 221 are injected. A secondary injection unit 240 is provided, and both units are driven by the same configuration and mechanism. The two units 230 and 240 are arranged on the diagonal crossing with the injection-side fixing plates 234 and 244 provided at the end, and two injection-side ball screws 232 and 242 provided on each diagonal. The tie bars 231 and 241 are provided, respectively, and the ejection side movable plates 233 and 243 that move along the tie bars 231 and 241 with the rotation of the ejection side ball screws 232 and 242, respectively. Further, plungers 235 and 245 are assembled to the movable plates 233 and 243, and the plungers 235 and 245 move in the axial direction in the cylinders 236 and 246 for storing the molten resin of the molding material. Then, when the plungers 235 and 245 are selectively advanced, the molten resin is selectively injected into both the primary and secondary fixed molds.

  Hereinafter, the operation of the electric injection molding apparatus 200 will be described with reference to FIG. In addition, about each drive of each opening-and-closing mechanism and an injection mechanism, it is performed by the same mechanism as the electric injection molding apparatus 1. FIG. First, as shown in FIG. 8A, the primary side fixed mold 220 and the movable mold 210 are clamped. Completion of mold clamping is detected by the load current value of the open / close motor as in the case of the electric injection molding apparatus 1. Thereafter, the molten resin is injected to the primary side by the movement of the injection side movable plate 233 from the primary side injection unit 230. Completion of injection is defined by a sensor that detects the state of filling of the molten resin into the cavity as described above. After the injection, after a certain holding time, the injection side movable plate 233 and the movable plate 13 move in the opening direction as shown in FIG. 8B.

  From the state of FIG. 8B, the mold moving ball screw 213 rotates and the movable mold 210 moves to the secondary side (FIG. 8C). Then, the movable mold 210 moved to the secondary side moves to the center fixed plate 3 side together with the open / close side movable plate 13 to be in a clamped state. This state is also detected by the motor load current value as in the primary side. Thereafter, as shown in FIG. 8D, the molten resin is injected from the secondary injection unit 240 to the secondary side by the movement of the injection side movable plate 243. After the completion of the injection is detected by the same sensor as that on the primary side, after a certain holding time elapses, the injection side movable plate 243 and the movable plate 13 are moved in the opening direction as shown in FIG. To do. The two-color molded product B can be collected by operating an air cylinder (not shown).

  The injection mechanism section 280 of the electric injection molding apparatus 200 is a plunger type of the electric injection molding apparatus 1 of FIG. 1 on both the primary side and the secondary side in two sets of injection units. However, the combination may be either a combination in which one is a plunger type and the other is a plunger in screw type in the electric injection molding apparatus 100 of FIG. 6, and a combination in which both are plunger in screw types.

  FIG. 9 shows a plan view of still another embodiment. The mold opening / closing mechanism 10 in the electric injection molding apparatus 300 performs a mold opening / closing operation with respect to the central fixed plate 3 by driving the ball screws 17 and 18 with the movable mold plate 13 being cantilevered with respect to the central fixed plate 3. On the other hand, the injection mechanism 290 is arranged such that the injection head 82 is offset by a certain amount L with respect to the center line of the mold opening / closing mechanism 10. The injection mechanism 290 includes a first injection-side fixed plate 81 and a second injection-side fixed plate 134 that are fixed at a predetermined interval from each other, and an injection-side movable plate 133 is interposed between them. In the same manner as in FIG. 1, two ball screws 137 and 138 are guided by two tie bars (not shown) penetrating on one diagonal and screwed through the other diagonal. It is designed to be driven.

  Both ends of these ball screws 137 and 138 and a tie bar (not shown) are supported by first and second injection-side fixed plates 81 and 134, and are injection operation members (such as plungers) fixed to the injection-side movable plate 133 ( The pushing member) injects molten resin from the tip of the injection head 82 through the center-side fixed plate 3 into the cavity formed in the clamped state of the fixed mold 11 and the movable mold 12 by the advance of the injection-side movable plate 133. To do.

  A runner, which is a passage for molten resin, is formed in the fixed mold 11. When the cavity has a longitudinal shape in a plan view (L direction in FIG. 9), molten resin is supplied from the center of the cavity and Rather than flowing left and right, the molten resin flows from one side (one end side) in the longitudinal direction of the cavity and flows to the opposite side (the other end side), so that the cavity is finally filled with the molten resin. There is a case where a tendency to obtain a high-quality resin molded product may be recognized.

  In that case, if the injection head 82 is positioned at the center of the cavity (the center line of the injection head 82 is aligned with the center line of the mold opening / closing mechanism 10), the runner to be formed on the fixed mold 11 or the like (from the center of the cavity) It must be extended to one end). On the other hand, if the injection head 82 is preliminarily positioned close to one end of the longitudinal cavity, that is, offset, the runner formation distance can be shortened, the mold can be easily manufactured, and the runner structure is simple. Can be.

  FIG. 10 shows still another embodiment. In the electric injection molding apparatus 350 of this embodiment, the configuration of the mold opening / closing mechanism 10, that is, the lower part of the movable mold plate 13 is supported by the rails 15 and 16 of the slide guide and the two ball screws 17 and 18 in a cantilever state. A mechanism similar to the configuration in which the movable plate 13 moves by passing through the diagonal of the movable plate 13 is also adopted on the injection mechanism 330 side. That is, the injection-side movable plate 333 has a bearing unit (FIGS. 1 and 3) fixed to a lower portion of the injection-side movable plate 333 with respect to the central fixed plate 3 by a slide guide that slides on linear rails 315 and 316 formed on the frame. Arranged so as to approach and separate. There is no tie bar (guide bar) for guiding the movable plate 333.

  Two ball screws 337 and 338 extend from the center fixed plate 3 to the injection mechanism 330 side, and these ball screws 337 and 338 are screwed to the injection side movable plate 333 at two diagonal points. The plate 333 is passed through. Each ball screw 337 and 338 is cantilevered without being supported by an end plate at each end, and pulleys 355 and 355 are attached to these cantilevered ends. The timing belt 356 laid around the pulleys 355 and 356 is driven by the injection side motor 352. As a result, the ball screws 337 and 338 rotate in the same direction at the same speed, and move the ejection-side movable plate 333. The injection side movable plate 333 moves the plunger 342 forward for resin injection.

  Thus, both the mold opening / closing mechanism 10 and the injection mechanism 330 side eliminate the tie bar and end plate, and both move the movable mold plate 13 and the injection side movable plate 333 by rotating the cantilevered ball screw. As a result, the number of parts is reduced and the apparatus configuration is particularly simple. Also, the apparatus can be configured in a compact manner, and the effect of simplification and miniaturization is great.

The partial notch perspective view as one Example of the electric injection molding apparatus of this invention. The partial expanded sectional view which expands and shows the opening-and-closing mechanism part of FIG. The front view which shows the slide guide of a movable plate. Explanatory drawing which shows the function of the sensor which controls injection quantity. Operation | movement explanatory drawing of the electric injection molding apparatus of FIG. The partial notch perspective view which shows the modification of the electric injection molding apparatus of FIG. The partial top view of the electric injection molding apparatus in which 2 color molding is possible. Operation | movement explanatory drawing of the 2 color molding of the electric injection molding apparatus of FIG. The top view which shows the example which the nozzle of the injection mechanism offset from the apparatus center. The top view which shows the Example which further simplified FIG. The front view which shows the example of the conventional electric injection molding apparatus.

Explanation of symbols

1,100,200,300,350 Electric injection molding apparatus 2 Frame 3 Center fixed plate 10,290 Opening / closing mechanism (mold opening / closing mechanism)
DESCRIPTION OF SYMBOLS 11 Fixed mold 12 Movable mold 13 Movable mold plate 14 Bearing unit 15, 16 Linear guide 17, 18 Opening and closing side ball screw 35, 36, 231, 241 Tie bar 30, 130, 280, 290, 330 Injection mechanism part (injection mechanism)
33, 133, 233, 243, 333 Injection side movable plate 34, 81, 134, 234, 244 Injection side fixed plate 37, 38, 232, 242 Injection side ball screw (ball screw)
42, 142, 235, 245, 342 Plunger 50 Drive mechanism (drive mechanism)

Claims (7)

A central fixed plate that supports the fixed mold of the mold;
A movable plate that is arranged so as to be movable toward and away from the central fixed plate and supports the movable mold of the mold;
A slide guide that receives the lower part of the movable plate and guides the movable plate so as to be slidable in the approaching / separating direction;
A mold opening / closing ball screw extending in a cantilevered state from the central fixed plate toward the movable mold plate;
An electric motor for opening and closing the mold that rotates the ball screw in the cantilever state in both forward and reverse directions, and moves the movable mold plate closer to and away from the center fixed plate;
The fixed mold and the movable mold are arranged on the opposite side of the movable mold plate with respect to the central fixed plate so as to face the mold opening / closing mechanism configured as described above, and the fixed mold and the movable mold are moved by the approach of the fixed mold plate and the movable mold plate. An injection mechanism including an injection electric motor that pushes the molten resin into the mold in the mold clamping state;
An electric injection molding apparatus comprising: A central fixed plate that supports the fixed mold of the mold;
A movable plate that is arranged so as to be movable toward and away from the central fixed plate and supports the movable mold of the mold;
A slide guide that receives the lower part of the movable plate and guides the movable plate so as to be slidable in the approaching / separating direction;
Two ball screws for opening and closing the mold that extend in a cantilevered state from the central fixed plate toward the movable mold plate and are screwed to the movable mold plate at two diagonal points;
An electric motor for opening and closing the mold that rotates the ball screw in the cantilever state in both forward and reverse directions, and moves the movable mold plate closer to and away from the center fixed plate;
The fixed mold and the movable mold are arranged on the opposite side of the movable mold plate with respect to the central fixed plate so as to face the mold opening / closing mechanism configured as described above, and the fixed mold and the movable mold are moved by the approach of the fixed mold plate and the movable mold plate. An injection mechanism including an injection electric motor that pushes the molten resin into the mold in the mold clamping state;
An electric injection molding apparatus comprising: The ball screw rotates in a cantilevered state when a rotational driving force of the motor for opening and closing the mold is transmitted to a portion of the ballscrew in the cantilevered state protruding outward from the movable mold plate. The electric injection molding apparatus described. The injection mechanism is
An injection-side movable plate that is disposed so as to be able to approach and separate from the central fixed plate or another fixed plate, and supports a plunger that pushes molten resin into the mold,
A guide mechanism for guiding the movable movable plate in the approaching / separating direction;
An injection ball screw extending from the central fixed plate or another fixed plate toward the injection side movable plate and screwed to the injection side movable plate;
An electric motor for injection in which the ball screw is rotated in both forward and reverse directions so that the injection-side movable plate approaches and separates from the central fixed plate or another fixed plate and the molten resin is pushed into the mold by the plunger. When,
The electric injection molding apparatus according to claim 1, comprising: The injection ball screw extends from the central fixed plate or another fixed plate toward the injection side movable plate and is screwed to the injection side movable plate, and a portion protruding from the injection side movable plate is fixed to the injection side. A rotation support force of the electric motor for injection is transmitted to the projecting portion of the ball screw to be supported by the plate or without the injection side fixing plate, and the ball screw is rotated. 4. The electric injection molding apparatus according to 4. The ejection side movable plate has two ball screws threaded on one set of diagonals, and two guide tie bars on another pair of diagonals, and the end portions of the tie bars and the ball screws are The electric injection molding apparatus according to claim 4, which is supported by an injection-side fixing plate. The ejection side movable plate has two pairs of ball screws screwed on a pair of diagonals, and there is no tie bar as a guide mechanism for the ejection side movable plate, and the lower part of the ejection side movable plate is received as the guide mechanism. A slide guide for slidably guiding the movable plate in the approaching / separating direction, and a portion of the ball screw that protrudes from the injection-side movable plate is in a cantilever state, and the portion of the injection motor is placed in that portion. The electric injection molding apparatus according to claim 4, wherein the rotational driving force is transmitted.

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