JP2014094480A - Injection molding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact size injection molding device in which rotation of a movable block by torque of a ball screw that generates at mold clamp time can be prevented, and degradation of axis core accuracy between a stationary mold and a movable that are mounted on a stationary block and a movable block is small.SOLUTION: A linear guide 20 is disposed in which at mold clamp time in which contact is performed between a movable mold 11M and a stationary mold 11S, a moment that rotates a movable block 17 generated by torque of a ball screw axis 18A is received to prevent degradation of axis core accuracy between a movable mold 11M and a stationary mold 11S.

Description

  The present invention relates to an injection molding apparatus having an improved mold clamping unit in a small injection molding machine.

  In recent years, there has been proposed a small injection molding machine as shown in Patent Document 1 in which a conventional screw is replaced with a rotor in order to reduce the size of an injection molding machine. This injection molding machine is an injection molding device that injects a plasticized material into a cavity of a molding die to injection mold a product. In this injection molding machine, a material is heated and plasticized, and a plasticizing block having a plasticizing pressure feeding mechanism for feeding while being kneaded is closely connected to the plasticizing block, and a plasticizing block is provided inside the plasticizing block. A metering block provided with a metering and feeding mechanism for metering and feeding the material fed by the pressure feeding mechanism and an injection mechanism for injecting the material metered and fed by the metering mechanism into the cavity are provided.

  The mold includes a fixed die plate (fixed die), and a movable die plate (movable) that moves forward and backward toward the fixed die plate to make the cavity substantially closed when abutting against the fixed die plate. Mold). The movable die plate is supported so as to be able to contact and separate from the fixed die plate while being guided by a plurality of tie bars. Further, the movable die plate is moved forward and backward with respect to the fixed die plate, and a mold clamping mechanism is provided with a movable die plate driving mechanism that generates a predetermined clamping force when the movable die plate contacts the fixed die plate. And a housing.

  The movable die plate drive mechanism is a mechanism that generates a mold clamping force by rotating a mold clamping ball screw that is screwed into a ball screw nut attached to a movable block that holds the movable die plate.

JP 2005-306028 A

  In the injection molding machine disclosed in Patent Document 1, a rotational moment that rotates the movable block via the ball screw nut is generated by the rotational force of the ball screw during mold clamping. Due to this rotational moment, the movable block rotates relative to the fixed block holding the fixed die plate, so the axis between the fixed mold mounted on the fixed block and the movable mold mounted on the movable block. There is a possibility of deteriorating the lead accuracy.

  The present invention has been made paying attention to the above circumstances, and its purpose is to prevent rotation of the movable block due to the rotational force of the ball screw generated at the time of mold clamping, and the fixed mold mounted on the fixed block and movable An object of the present invention is to provide a small-sized injection molding apparatus with little deterioration of axial accuracy between a movable mold mounted on a block.

An aspect of one aspect of the present invention includes a plasticizing part in which a scroll-type metering mechanism that heats and plasticizes a material and feeds the material while kneading is provided, and is supplied from the plasticizing part. An injection mechanism for injecting the resin material into the cavity is connected, and a fixed block that holds the fixed mold and a movable mold that can move in the direction of moving toward and away from the fixed mold are held, and moves forward and backward toward the fixed block. When the movable mold and the fixed mold come into contact with each other, a movable block that forms the cavity in a substantially closed space between the movable mold and the fixed mold, and the movable block by rotation of the ball screw shaft An injection molding apparatus having a movable block driving mechanism for moving a movable block in a direction in which the movable block is moved toward and away from the fixed block and generating a predetermined clamping force when the movable mold and the fixed mold are in contact with each other ,Previous Deterioration of the axial accuracy of the movable mold and the fixed mold in response to a moment for rotating the movable block generated by the rotational force of the ball screw shaft when the mold is clamped between the movable mold and the fixed mold. An injection molding apparatus comprising a rotational moment receiving portion for preventing.
In the above configuration, according to the present invention, the movable block is fixed at a predetermined distance from the fixed block by the linear guide and the plurality of tie bars, and the movable block is moved forward and backward with respect to the fixed block via the linear guide. Thus, the rotation of the movable block due to the rotational force of the ball screw generated during mold clamping is prevented by the rigidity of the linear guide. As a result, deterioration of the axial center accuracy between the cavities of the fixed mold attached on the fixed block and the movable mold attached on the movable block is prevented.

Preferably, the movable block drive mechanism has a plurality of tie bars that are movably supported between the movable block and the fixed block in a mold opening / closing direction of the movable mold and the fixed mold. The part is provided in parallel with the tie bar, and has a linear guide that guides a linear motion that translates the movable block in a mold opening / closing direction of the movable mold and the fixed mold. This is an injection molding apparatus.
In the above configuration, the movable block is fixed at a predetermined distance from the fixed block by the linear guide and the plurality of tie bars, and the movable block is moved forward and backward with respect to the fixed block via the linear guide. The rotation of the movable block due to the rotational force of the ball screw generated during tightening is prevented by the rigidity of the linear guide. Thereby, it is possible to prevent deterioration of the axial accuracy between the cavities of the fixed mold attached to the fixed block and the movable mold attached on the movable block.

  Preferably, the movable block driving mechanism includes a mold clamping block to which a base end portion of the ball screw shaft is fixed, and a ball screw nut attached to the movable block and screwed with a distal end portion of the ball screw shaft. A mold clamping that generates a predetermined clamping force when the movable block and the fixed mold are brought into contact with each other by moving the movable block in the direction of contacting and separating from the fixed block by the rotation of the ball screw shaft. The injection molding apparatus according to claim 1, further comprising an apparatus.

  Preferably, a mold clamping torque absorbing unit for absorbing a mold clamping torque between the movable mold and the fixed mold is disposed between the movable block and the mold clamping device to absorb the mold clamping torque. The unit includes a unit base that is supported to be movable toward and away from the movable block, a thrust bearing installed on the movable block side of the unit base, and a plurality of units that connect between the movable block and the unit base. The rotational moment receiving portion is connected to the movable block and the unit base via the thrust bearing during mold clamping, thereby rotating the ball screw shaft during mold clamping. Due to the force, a rotational moment acting in the direction of rotating the movable block via the ball screw nut is applied to the thrust. An injection molding apparatus according to claim 3, characterized in that it comprises a torque converter for preventing transmission of the torque to the movable block by converting the rotational force of the bearing.

  According to the present invention, the rotation of the movable block due to the rotational force of the ball screw generated during mold clamping can be prevented, and the axial accuracy between the fixed block and the fixed mold mounted on the movable block and the movable mold can be reduced. A small injection molding apparatus with little deterioration can be provided.

The top view which shows the schematic structure of the whole injection molding apparatus of the 1st Embodiment of this invention. The side view which shows the mold clamping state of the injection molding apparatus of 1st Embodiment. The side view which shows the mold opening state of the injection molding apparatus of 1st Embodiment. 4A is a sectional view taken along line 4A-4A in FIG. 3, and FIG. 4B is a sectional view taken along line 4B-4B in FIG. The cross-sectional view which shows the linear guide of the injection molding apparatus of 1st Embodiment. The perspective view which shows an example of the linear guide of the injection molding apparatus of 1st Embodiment. The cross-sectional view which shows the modification of the injection molding apparatus of 1st Embodiment. The side view which shows the mold opening state of the injection molding apparatus of the 2nd Embodiment of this invention. The longitudinal cross-sectional view of the principal part which shows the connection part of the thrust bearing of the injection molding apparatus of 2nd Embodiment. The longitudinal cross-sectional view of the principal part which shows the thrust bearing of the injection molding apparatus of 2nd Embodiment. The side view which shows the mold clamping state of the injection molding apparatus of 2nd Embodiment.

[First Embodiment]
(Constitution)
1 to 6 show a first embodiment of the present invention. FIG. 1 is a plan view showing an overall schematic configuration of the injection molding apparatus according to the first embodiment, and FIG. 2 is a side view. The injection molding machine 10 in the present embodiment includes a mold unit 11 as a mold and a mold clamping device (movable block drive mechanism) 12 for clamping the mold unit 11.

The mold unit 11 in the present embodiment has a fixed-side mold (fixed mold) 11S and a movable-side mold (movable mold) 11M, and a cavity 2 (see FIG. 4 (B)) is formed.
The injection molding machine 10 further includes a resin material plasticizing and sending device 14 that plasticizes and sends a resin material, and a resin metering and injection device 13 that pumps a predetermined amount of molten resin. A predetermined amount of molten resin pumped from the resin metering device 13 is supplied to a cavity (not shown) formed in the mold unit 11.

  The resin material plasticizing and feeding device 14 of the present embodiment includes a plasticizing portion in which a scroll-type metering and feeding mechanism is provided that heats and plasticizes the resin material and feeds it while kneading. The scroll-type metering mechanism includes a barrel, a rotor, rotor driving means, and heating means (all not shown). This scroll-type metering delivery mechanism is housed in and accommodated in the fixed block 21 and the casing 22.

  Here, the rotor driving means is installed in the casing 22. A rotor drive motor 23 constituting a part of the rotor drive means is mechanically connected to the rotor. The heating means heats and softens and melts the resin present in the plasticizing delivery device 14.

  The resin metering injection device 13 includes a fixed block 21 that holds the fixed mold 11S, a hot runner nozzle (not shown) inserted through the fixed mold 11S, an injection plunger (not shown), and an injection / metering motor 24. Including. The injection plunger is slidably fitted to the chamber and pumps the resin interposed in the chamber by a predetermined amount toward the resin passage side of the hot runner nozzle. The injection plunger is mechanically connected to the injection / metering motor 24 via a speed reducer and a power transmission mechanism (not shown). The rotation of the rotor by the rotor drive motor 23 and the advance / retreat operation of the injection / metering motor 24 can be combined to inject the resin contained in the chamber into the cavity 2 of the mold unit 11 from the hot runner nozzle.

  The fixed mold 11 </ b> S of the mold unit 11 is fixed to the fixed block 21, and the movable mold 11 </ b> M is held by the movable block 17. Here, the fixed mold 11S and the movable mold 11M are disposed to face each other with a PL (parting line) interposed therebetween. The movable mold 11M is supported so as to be movable in the mold opening / closing direction (left-right direction in FIGS. 1 and 2) with respect to the fixed mold 11S.

  Further, as shown in FIG. 4A, the fixed die 11S is provided with a nozzle hole 3 of a hot runner nozzle at a position corresponding to the cavity 2 at the center position, and a plurality of positioning pin holders are provided on the outer peripheral portion. A hole 4 is formed. As shown in FIG. 4B, positioning pins 5 are provided at positions corresponding to the pin receiving holes 4 of the fixed die 11S on the outer peripheral portion of the movable die 11M. The movable block 17 incorporates an ejector device (not shown) for taking out the molded product from the cavity 2 of the movable mold 11M.

The mold clamping device 12 in this embodiment includes a mold clamping block 15, a mold clamping motor 16 attached to the mold clamping block 15, and a ball screw that mechanically connects the mold clamping motor 16 and the movable block 17. Mechanism 18.
Further, four tie bars 19 project from the clamping block 15 toward the fixed block 21 side. The mold clamping block 15 is formed in a rectangular shape having substantially the same size as the fixed block 21 and the movable block 17. The base end portions of the four tie bars 19 are respectively disposed at the four corner portions of the mold clamping block 15. As shown in FIG. 3 and FIGS. 4A and 4B, the tip portions of the four tie bars 19 penetrate the movable block 17 and are fixed to the fixed block 21. Thereby, in this embodiment, the movable block 17 is supported by the four tie bars 19 so as to be movable in the mold opening / closing direction of the movable mold 11M and the fixed mold 11S with respect to the fixed block 21.

  A linear guide 20 connected to the lower part of the movable block 17 is provided on the installation table 1 of the injection molding machine 10. In the present embodiment, two linear guides 20 are disposed on the installation table 1. The linear guide 20 has a guide rail 20a fixed on the installation base 1 and a slider 20b mounted so as to straddle the guide rail 20a. The guide rail 20a is disposed in parallel with the mold opening / closing direction of the movable mold 11M and the fixed mold 11S.

  FIG. 5 is a sectional view of the linear guide 20, and FIG. 6 is a perspective view. Here, the guide rail 20a is formed with two upper and lower rolling element rolling grooves 31, 32, 33, and 34 extending in the axial direction on the left and right outer surfaces. The slider 20b has two left and right leg portions 35 and 36 arranged on the left and right sides of the guide rail 20a, and a connecting portion 37 arranged on the upper side of the guide rail 20a and connecting the upper ends of the leg portions 35 and 36. . Rolling body rolling grooves 38, 39, 40, 41 are formed on the inner side surfaces of the left and right leg portions 35, 36, respectively. Between the rolling element rolling grooves 31, 32, 33, and 34 of the guide rail 20a and the rolling element rolling grooves 38, 39, 40, and 41 of the slider 20b, there is a rolling passage into which the rolling element 42 is inserted. Is formed. Then, the rolling element 42 rolls in the rolling path between the rolling element rolling grooves 31, 32, 33, 34 of the guide rail 20a and the rolling element rolling grooves 38, 39, 40, 41 of the slider 20b. Thus, the slider 20b moves linearly relative to the guide rail 20a.

In the present embodiment, the movable block 17 is fixed on the sliders 20 b of the two linear guides 20 via the connecting members 43. Further, the fixed block 21 and the casing 22 are fixed on the installation table 1 through a fixed table 44.
The ball screw mechanism 18 includes a ball screw shaft 18A coupled to the mold clamping motor 16 and a ball screw nut 18N attached to the movable block 17. The ball screw shaft 18A is screwed to the ball screw nut 18N. Furthermore, the rotating shaft of the mold clamping motor 16 and the ball screw shaft 18A are connected via a reduction gear (not shown). The motor 16 reduces the rotational speed of the motor with a reduction gear (not shown) that obtains rotational power to rotate the ball screw shaft 18A, and the ball screw nut 18N moves the movable block 17 back and forth. Accordingly, by driving the mold clamping motor 16, the movable block 17 is guided by the four tie bars 19 together with the movable mold 11M, and the mold opening / closing direction of the movable mold 11M and the fixed mold 11S along the linear guide 20 is achieved. Can be moved in parallel. More specifically, in the case of mold clamping operation, the movable mold 11M is pressed against the fixed mold 11S with a predetermined pressure (see FIGS. 1 and 2), and in the case of mold opening operation, the movable mold 11M is pulled away from the fixed mold 11S ( (See FIG. 3).

  In the present embodiment, the two linear guides 20 receive the moment for rotating the movable block 17 generated by the rotational force of the ball screw shaft 18A when the mold is clamped between the movable mold 11M and the fixed mold 11S. ing. Thereby, the rotational moment receiving part which prevents the deterioration of the axial center precision of the movable mold | type 11M and the fixed mold | type 11S by the two linear guides 20 is formed.

(Function)
Next, the operation of the above configuration will be described. When the injection molding apparatus according to the present embodiment is used, the mold clamping device 12 is driven. By driving the mold clamping motor 16, the movable block 17 is guided by the four tie bars 19 together with the movable mold 11M, and parallel to the mold opening / closing direction of the movable mold 11M and the fixed mold 11S along the linear guide 20. Move to. More specifically, in the case of mold clamping operation, the movable mold 11M is pressed against the fixed mold 11S with a predetermined pressure, and in the case of mold opening operation, the movable mold 11M is pulled away from the fixed mold 11S.

  Further, during the mold clamping operation, the rotational power of the mold clamping motor 16 is reduced by a speed reducer (not shown) to rotate the ball screw shaft 18A. By the rotation of the ball screw shaft 18A, the movable block 17 is advanced in the mold closing direction by the ball screw nut 18N. When the movable mold 11M comes into contact with the fixed mold 11S, a predetermined mold clamping force is generated. At the time of clamping, a moment for rotating the movable block 17 through the ball screw nut 18N is generated by the rotational force of the ball screw shaft 18A. At this time, the moment for rotating the movable block 17 can be received by the linear guide 20 connected to the movable block 17. Therefore, it is possible to prevent deterioration of the axial accuracy of the movable mold 11M and the fixed mold 11S attached to the fixed block 21 and the movable block 17, respectively.

(effect)
Therefore, the above configuration has the following effects. That is, in the injection molding apparatus according to the present embodiment, the two linear guides generate moments for rotating the movable block 17 generated by the rotational force of the ball screw shaft 18A during mold clamping in which the movable mold 11M and the fixed mold 11S are brought into contact with each other. It can be received by 20 stiffness. Accordingly, it is possible to provide a small-sized injection molding apparatus including a plasticizing part in which a scroll-type metering mechanism that can prevent deterioration of the axial center accuracy of the movable mold 11M and the fixed mold 11S is provided. it can.

  In the present embodiment, an example in which two linear guides 20 are arranged on the installation table 1 is shown, but a configuration in which one linear guide 20 is arranged on the installation table 1 may be used. In addition, as shown in FIG. 7, two linear guides 20 are provided on each of the upper, lower, left and right four surfaces of the movable block 17 so that the ball screw shaft 18A is clamped when the movable mold 11M and the fixed mold 11S are in contact with each other. You may make it the structure which further raises the rigidity of the linear guide 20 which receives the moment which rotates the movable block 17 which generate | occur | produces with a rotational force. In this modification, fixed bases are arranged on the four surfaces of the movable block 17 in the vertical and horizontal directions. This is particularly advantageous when the entire injection molding machine 10 is placed vertically along the vertical direction with respect to the floor surface.

[Second Embodiment]
(Constitution)
8 to 11 show a second embodiment of the present invention. This embodiment is a modification of the injection molding machine 10 of the first embodiment (see FIGS. 1 to 6). 8 to 11, the same parts as those in FIGS. 1 to 6 are denoted by the same reference numerals, and the description thereof is omitted. In the present embodiment, a mold clamping torque absorbing unit 51 for absorbing mold clamping torque between the movable mold 11M and the fixed mold 11S between the movable block 17 and the mold clamping apparatus 12 of the first embodiment. Is provided.

  The mold clamping torque absorbing unit 51 includes a unit base 52 that is supported so as to be able to contact and separate from the movable block 17. The unit base 52 is set to have substantially the same external dimensions as the movable block 17. And the tie bar insertion hole is formed in the four corner | angular parts of the unit base 52, and the four tie bars 19 are each inserted.

  Further, a ball screw nut 18N of the ball screw mechanism 18 is fixed to the end surface of the unit base 52 on the mold clamping device 12 side. A slider 54 is fixed to the lower surface of the unit base 52 via a connecting member 53. The slider 54 has the same configuration as the slider 20b of the first embodiment.

  A thrust bearing 55 is installed on the end surface of the unit base 52 on the movable block 17 side. As shown in FIG. 10, the thrust bearing 55 is formed by, for example, a single type thrust ball bearing. As shown in FIG. 9, the thrust bearing 55 includes two bearing rings 55a and 55b, a plurality of balls 55c sandwiched between the two bearing rings 55a and 55b, and a cylindrical cover 55d. An abutting member 56 is fixed to the outer surface of the outer bearing ring 55a.

  A plurality of mold opening links 57 are disposed between the movable block 17 and the unit base 52. The mold opening link 57 has an arm 58 having one end fixed to the unit base 52 via a fixing pin 59. A long hole 60 is formed on the free end side of the arm 58. A fixed pin 61 fixed to the movable block 17 is inserted into the long hole 60.

  In the present embodiment, the rotational moment receiving portion connects the movable block 17 and the unit base 52 via the thrust bearing 55 at the time of mold clamping, so that the rotational force of the ball screw shaft 18A at the time of mold clamping Rotational moment conversion means for preventing transmission of the rotational moment to the movable block 17 by converting the rotational moment acting in the direction of rotating the movable block 17 through the ball screw nut 18N into the rotational force of the thrust bearing 55 is provided.

(Action / Effect)
Next, the operation of the above configuration will be described. In the present embodiment, when the mold is opened, the unit base 52 is pulled toward the mold clamping device 12 via the ball screw nut 18N by the rotational force of the ball screw shaft 18A as shown in FIG. At this time, the pulling force of the unit base 52 is transmitted to the movable block 17 via the mold opening link 57, and the movable block 17 and the movable mold 11M are integrally moved in the mold opening direction.

  At the time of mold clamping, the unit base 52 is pushed out toward the movable block 17 via the ball screw nut 18N by the rotational force of the ball screw shaft 18A. By this pressing force, the unit base 52 is brought into contact with the movable block 17 via the thrust bearing 55. Thereafter, the movable block 17 is moved integrally with the unit base 52 along the linear guide 20 in the mold closing direction of the movable mold 11M and the fixed mold 11S while being guided by the four tie bars 19 together with the movable mold 11M.

  At the end of the mold clamping operation, the unit base 52 is held in contact with the movable block 17 via the thrust bearing 55 as shown in FIG. As a result, the rotational moment acting in the direction of rotating the movable block 17 via the ball screw nut 18N can be converted into the rotational force of the thrust bearing 55 by the rotational force of the ball screw shaft 18A at the time of mold clamping. And mold clamping torque between the fixed mold 11S and the fixed mold 11S can be absorbed. At this time, since the rotational moment is not transmitted to the movable block 17, more accurate mold clamping can be performed.

  Furthermore, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the present invention.

    2 ... cavity, 11S ... fixed mold, 11M ... movable mold, 12 ... mold clamping device (movable block drive mechanism), 17 ... movable block, 18A ... ball screw shaft, 20 ... linear guide (rotational moment receiving part), 21 ... fixed block.

Claims (4)

An injection mechanism that includes a plasticizing portion that is internally provided with a scroll-type metering and feeding mechanism that heats and plasticizes the material and feeds it while kneading, and injects the molten resin material supplied from the plasticizing portion into the cavity And a fixed block that holds the fixed mold,
A movable mold that is movable in a direction of moving toward and away from the fixed mold is held, and when the movable mold and the fixed mold come into contact with each other, the movable mold moves forward and backward toward the fixed block. A movable block that forms the cavity in a substantially closed space with the fixed mold;
A movable block drive that generates a predetermined clamping force when the movable block and the fixed die are brought into contact with each other by moving the movable block in the direction of contact with and away from the fixed block by rotation of a ball screw shaft. In an injection molding apparatus having a mechanism,
Deterioration of axial accuracy of the movable mold and the fixed mold in response to a moment for rotating the movable block generated by the rotational force of the ball screw shaft during mold clamping in which the movable mold and the fixed mold are brought into contact with each other. An injection molding apparatus characterized in that a rotational moment receiving portion is provided to prevent this. The movable block drive mechanism has a plurality of tie bars that are movably supported between the movable block and the fixed block in a mold opening / closing direction of the movable mold and the fixed mold,
The rotation moment receiving portion includes a linear guide that is arranged in parallel with the tie bar and guides a linear motion that translates the movable block in a mold opening / closing direction of the movable mold and the fixed mold. Item 2. The injection molding apparatus according to Item 1. The movable block drive mechanism includes a mold clamping block to which a base end portion of the ball screw shaft is fixed,
A ball screw nut attached to the movable block and screwed with a tip of the ball screw shaft;
A mold clamping that generates a predetermined clamping force when the movable block and the fixed mold are brought into contact with each other by moving the movable block in the direction of contacting and separating from the fixed block by the rotation of the ball screw shaft. The injection molding apparatus according to claim 1, further comprising an apparatus. A clamping torque absorption unit for absorbing clamping torque between the movable mold and the fixed mold is disposed between the movable block and the clamping device,
The mold clamping torque absorbing unit is supported by a unit base that is detachable from the movable block;
A thrust bearing installed on the movable block side of the unit base;
It is composed of a plurality of mold opening links connecting between the movable block and the unit base,
The rotational moment receiving portion connects the movable block and the unit base via the thrust bearing at the time of mold clamping, so that the rotational force of the ball screw shaft at the time of mold clamping causes the ball screw shaft to The rotary moment converting means for preventing transmission of the rotational moment to the movable block by converting a rotational moment acting in a direction of rotating the movable block into a rotational force of the thrust bearing. 3. The injection molding apparatus according to 3.

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