JP2006240087A - Injection apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an injection apparatus which can be launched to inject a molten material of a plastic, metal, or the like in a short time from an optional point of time. <P>SOLUTION: In the injection apparatus 10 for injection-molding the molten material M stored in the front part of the inner hole 36 of a heating cylinder 11 by pressurizing it by a plunger 14, a first driving part 30 advancing/driving the plunger 14 is set to be launched by the advancing speed of the first driving part 30 alone to push the plunger 14 after moving an idle running distance D, and a second driving part 31 is connected directly to the plunger 14. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an injection apparatus that can easily inject a molten material of plastic or metal.

  In the injection molding of the molten material, if the molten material is not injected and filled into the mold cavity while it has sufficient fluidity, filling failure, distortion, etc. occur in the molded product. Therefore, it is required to inject the molten material as fast as possible within a range in which jetting or burring does not occur. In particular, this problem is remarkable when the molded product is thin or the molten material is a metal having a high thermal conductivity. In addition, in addition to the flow rate of the molten material during injection / filling, the rise time of injection is required to be short, particularly for thin-walled molded products.

  For this reason, a technique for increasing the rise time of a hydraulic cylinder, which is an actuator for injection advancement, is disclosed (see Patent Document 1). According to Patent Document 1, when the set time of the timer elapses after the control circuit outputs a signal to the flow control proportional valve and the pressure control proportional valve, the signal is output to the direction switching valve. Since the hydraulic cylinder is operated by injection when the oil pressure increases, the movement of the preceding portion of the hydraulic oil is accelerated and passes through the direction switching valve instantaneously, so that the rise time is shortened.

  However, according to the technique disclosed in Patent Document 1, although the pressure rise time of the hydraulic oil supplied to the hydraulic cylinder for injecting and driving the resin is sufficiently short, the pressure rise of the hydraulic oil in the hydraulic cylinder itself is from zero. Since it starts, it takes a considerable time according to the volume of the hydraulic cylinder. For this reason, the rise time for the hydraulic cylinder to reach a predetermined speed is several tens of milliseconds, which is not sufficiently short. Furthermore, since there is inertia in a movable part related to resin injection, such as an actuator or a screw, there is a limit to shortening the rise time. This problem is the same even when the actuator uses other means such as a servo motor instead of hydraulic pressure.

In addition, as mentioned above, in injection molding, it is a principle to start up at a high speed from the beginning of injection / filling. However, since cold slag of molten material does not flow into the molded part of the mold cavity, the core of the mold is used. When there is a purpose such as preventing jetting or preventing jetting, the injection / filling speed is first set to a relatively low speed and then started up at a high speed to inject the molten material into the cavity corresponding to the molded product. Is required. When such injection molding is executed by the method of Patent Document 1, even the characteristics of Patent Document 1 cannot be exhibited at the time when the injection speed is switched from low speed to high speed, and the rise time of the injection speed cannot be shortened.
JP-A-8-25436

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an injection apparatus capable of starting up and injecting a plastic or metal molten material from an arbitrary point in a short time.

  That is, the invention of claim 1 is directed to an injection device that performs injection molding by pressurizing the molten material stored in the front portion of the heating cylinder inner hole with a plunger, and the first drive unit that drives the plunger forward is the first drive. The injection device is provided so as to press the plunger after rising by a forward speed of only a portion and moving an air transport distance.

  A second aspect of the present invention relates to the injection apparatus according to the first aspect, wherein a second drive unit is directly connected to the plunger.

  A third aspect of the present invention relates to the injection apparatus according to the second aspect, wherein the output of the second drive unit is smaller than the output of the first drive unit.

  According to a fourth aspect of the present invention, there is provided the injection according to the second aspect, wherein when the plunger is advanced by the second driving portion, an engaging portion is provided to advance the first driving portion with a gap in the idle feeding distance. Related to the device.

  The invention according to claim 1 is an injection apparatus in which a molten material stored in a front portion of a heating cylinder inner hole is pressurized by a plunger and injection-molded, and the first drive unit that drives the plunger forward is only the first drive unit. Since it is provided to press the plunger after rising at the forward speed and moving the air transport distance, the molten material can be injected and started at a very high speed.

  The invention of claim 2 is the invention according to claim 1, wherein the plunger is directly connected to the second drive portion, so that the molten material is raised and injected in a short time from an arbitrary point after low-speed injection. Can do.

  According to a third aspect of the present invention, in the second aspect of the present invention, since the output of the second drive unit is smaller than the output of the first drive unit, the molten material can be reduced at low cost and with a small volume. An injection apparatus that can be started up and injected in a short time from an arbitrary point after injection is obtained.

  According to a fourth aspect of the present invention, in the second aspect of the present invention, there is provided an engaging portion that advances the first drive portion with the gap in the idle distance when the plunger is advanced by the second drive portion. Therefore, it is possible to obtain an injection apparatus that can easily start up and inject a molten material in a short time from an arbitrary point after low-speed injection.

  Embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing a state from the start of injection to execution of the first injection in the injection apparatus of the present invention, FIG. 2 is a schematic cross-sectional view showing a state during execution of the second injection in the injection apparatus of the present invention, and FIG. It is a graph which shows the behavior of the plunger in the injection process performed by the injection device of the present invention.

  The injection apparatus 10 includes a thick cylindrical heating cylinder 11, a nozzle 13 having a through hole that is fixed to the front end surface of the heating cylinder 11 and communicates with the inner hole 36 of the heating cylinder 11, and a front portion of the inner hole 36 of the heating cylinder 11. The plunger 14 is inserted into the inner hole 36 so as to be reciprocally movable while sealing the molten material M stored therein, the first drive unit 30 connected to the plunger 14 via the base member 15 and the connecting member 16, and the plunger 14. The second drive unit 31 fixed via the base 15, the drive unit 33 that controls and drives the first drive unit 30 and the second drive unit 31 that are actuators, and a signal transmitted to the drive unit 33 to transmit the plunger 14 And a control means 32 for controlling the operation.

  The molten material M is in a state in which plastic, light metal, or the like is melted, and is supplied from the supply port 12 provided near the front end portion of the heating cylinder 11 to the front portion of the inner hole 36 for each molding cycle. A plasticizing device (not shown) is connected to the supply port 12. When the molten material M is plastic, the plasticizing apparatus is a known extruder including a screw and another heating cylinder into which the screw is rotatably inserted. Further, when the molten material M is a light metal, the above-described extruder is adopted, or a cylindrical billet is inserted into the opening of the inner hole 36 on the rear end surface of the heating cylinder 11 without providing the supply port 12. Is melted to obtain a molten material M.

  The plunger 14 is formed so that the diameter of at least its tip is slightly smaller than the inner diameter of the inner hole 36 so that the molten material M does not leak to the rear part of the plunger 14. The rear end surface of the plunger 14 is fixed to the longitudinal center portion of the base 15 made of a prism having sufficient bending strength. A cylindrical connecting member 16 is fixed to the surface of the base 15 opposite to the surface to which the plunger 14 is fixed, with the central axis of the through hole being coaxial with the central axis of the plunger 15. An engaging portion 35 formed by reducing the diameter of the through hole is formed at an end portion of the connecting member 16 that is not fixed to the base 15.

  The engaging portion 35 of the connecting member 16 engages with a head portion 34 that has a diameter larger than that of the first rod 17 and is fixed to the front end surface of the first rod 17 that is the output shaft of the first driving portion 30. One rod 17 is configured to be pulled by the connecting member 16. The first rod 17 is guided by the head portion 34 through the through hole of the connecting member 16 and can reciprocate during the air feeding distance D. That is, the head 34 that has been engaged with the engaging portion 35 moves the air feeding distance D when the first driving portion 30 is driven forward and the first rod 17 moves forward. Immediately thereafter, the front end surface of the head 34 is brought into contact with the side surface of the base 15. At this time, the higher the forward speed of the first drive unit, the greater the impact force between the head 34 and the base 15 and damage both. In order to prevent this, it is preferable that a cushioning member made of an elastic member is provided on one or both of the front end surface of the head 34 and the side surface of the base 15 although not shown.

  The first drive unit 30 is a hydraulic cylinder device, and includes a support body 23 attached in common to a member (not shown) to which the heating cylinder 11 is attached, a first cylinder 21 fixed to the support body 23, and a first cylinder 21. The first piston 19 is inserted into the first piston 19 so as to be reciprocally movable and fluid-tight, and the first rod 17 is fixed to the center of the first piston 19 and inserted through the support 23 and the first cylinder 21 in a fluid-tight manner. The internal space of the first cylinder 21 is divided into two by the first piston 19, and the space close to the plunger 14 is a first retreat chamber 26, and the space far from the plunger 14 is a first advance chamber 24. The first drive unit 30 is not limited to the hydraulic cylinder device, and may be another actuator such as a servo motor.

  The second drive unit 31 is a hydraulic cylinder device, which is fixed to both ends of the base 15 and is directly connected to the plunger 14 without a movable part such as the connecting member 16. The second drive unit 31 includes a support 23 that is commonly attached to a member (not shown) to which the heating cylinder 11 is attached, a second cylinder 22 that is fixed to the support 23, a reciprocating motion to the second cylinder 22, and a liquid. It consists of a second piston 20 fitted in a compact manner, and a second rod 18 that is fixed to the center of the second piston 20 and passes through a support 23 and a second cylinder 22 in a fluid compact manner. The internal space of the second cylinder 22 is divided into two parts by the second piston 20, and the space close to the plunger 14 is a second retreat chamber 27 and the space far from the plunger 14 is a second advance chamber 25. The second drive unit 31 is not limited to the hydraulic cylinder device, and may be another actuator such as a servo motor. Further, as shown in FIG. 3, since the second drive unit 31 is provided to start injection at a relatively low speed, the output of the second drive unit 31 is the first for driving the injection at a relatively high speed. It is set smaller than the output of one drive unit. Furthermore, the second drive unit 31 does not allow the cold slag of the molten material to flow into the molded part of the mold cavity, thereby preventing the core of the mold from collapsing, and for the purpose of preventing jetting, etc. Although the filling rate is initially set to be relatively low, it may not be provided if it is not necessary.

  In the first drive unit 30 and the second drive unit 31, the first advance chamber 24, the second advance chamber 25, the first reverse chamber 26, and the second reverse chamber 27 are a hydraulic pump, a switching valve, a pressure adjustment valve, and a flow rate adjustment. The first rod 17 and the second rod 18 are controlled to move forward and backward by being connected to a driving means 33 such as a valve. The driving unit 33 is controlled by a signal transmitted from the control unit 32. The control means 32 is configured based on a microprocessor, and inputs the position signals of the first rod 17 and the second rod 18 detected by the first position detector 28 and the second position detector 29, respectively, and is preset and stored. A signal based on the result calculated by the position setting value and the position signal is output to the drive means 33.

  Next, the molding operation of the injection apparatus 10 will be described in detail. First, the injection device 10 is moved to bring the nozzle 13 into contact with a mold (not shown) having a cavity. At this time, the molten material M in an amount necessary for one or a plurality of molding cycles is stored in the front portion of the inner hole 36 of the heating cylinder 11, and the predetermined amount is detected by a position detector 29 that detects the position of the plunger 14. Detected and controlled. As shown in FIG. 3, the position of the plunger 14 detected and controlled is the measurement position P0. Further, as shown in FIG. 1, the first rod 17 of the first driving means 30 is controlled to be at a position further retracted from the measuring position P0 by a distance corresponding to the idle feeding distance D.

  The control means 32 transmits an injection start signal to the drive means 33. The drive means 33 supplies the second advance chamber 25 with pressure oil whose pressure and flow rate are adjusted based on the injection start signal. As shown in FIG. 3, the second rod 18 moves forward, and the plunger 14 moves forward from the metering position P0 to move the molten material M to the mold cavity (not shown) through the nozzle 13 at a predetermined speed. 1 shot. At this time, the first rod 17 (first driving unit 30) engaged with the connecting member 16 by the engaging portion 35 moves forward together with the plunger 14.

  When the position of the plunger 14 detected by the second position detector 29 reaches the preset switching position P1, the control means 32 supplies the pressure oil whose pressure and flow rate of the driving means 33 are adjusted to the first advance chamber 24. And the speed of only the first drive unit 30 is increased. The speed of the first drive unit 30 rises at a time determined according to the pressure oil discharge capacity of the drive means 33, the volume of the first advance chamber 24, the inertia of the first rod 17, and the like. Then, the first drive unit 30 moves forward through the air transport distance D. The flying distance D is preferably set to be larger than the distance required for the rising speed to reach a predetermined steady value after the first drive unit 30 starts moving. However, the flying distance D may be shorter than the sufficiently long distance as described above, and even in that case, it has the effect of shortening the rise time of the speed of the plunger 14.

  The head 34 fixed to the front end surface of the first rod 17 collides with the side surface of the base 15 at a high speed after moving the flying distance D, and instantaneously switches the forward speed of the plunger 14 from the low speed to the high speed P2. Starts. At this time, since the speed of the plunger 14 changes shockably, it becomes oscillating, but the buffer member relieves the vibration as described above.

  Note that the position at which the forward speed of the plunger 14 is actually switched from the low speed to the high speed P2 is slightly forward from the set value of the switching position P1. This is because the plunger 14 is moved forward by the second drive unit 31 while the first drive unit 30 moves through the flying distance D. However, since the moving speed by the second drive unit 31 is relatively low and the speed at which the first drive unit 30 moves through the idle transport distance D is relatively high, the set value of the switching position P1 and the actual value are actually set. The distance from the low-speed to high-speed P2 switching position is small. Nevertheless, if this distance becomes a problem, based on the forward speed setting values of the first drive unit 30 and the second drive unit 31, the distance from the switching position P1 to the position where the low speed is actually switched to the high speed P2 is reached. This can be solved by calculating the distance in advance and controlling it by adding the value to the set value of the switching position P1.

  The position of the plunger 14 that injects and fills the molten material M at the high speed P2 in this way is detected by the first position detector 28 or the second position detector 29, and the detected position becomes the predetermined deceleration position P3. When reaching, the control means 32 transmits a signal to the drive means 33 to brake the first drive section 30 and the second drive section 31. In addition, although the deceleration position P3 is shown in the case of one position, a plurality of deceleration positions P3 may be provided so that the injection speed is gradually reduced or increased again.

  The decelerated plunger 14 stops at the stop position P4 and finishes the second injection, and the molten material M filled in the mold cavity is cooled and solidified by the mold. Then, a new molten material M is supplied from the supply port 12, and the plunger 14 is retracted to the measurement position P 0 detected by the first position detector 28 or the second position detector 29. Thereafter, the first drive unit 30 retracts the first rod 17 until it engages with the engagement unit 35, and one molding cycle is completed.

  In addition, this invention includes what can be implemented in the aspect which added various change, correction, improvement, etc. based on the knowledge of those skilled in the art. Further, it goes without saying that any of the embodiments to which the above-mentioned changes are added is included in the scope of the present invention without departing from the gist of the present invention.

It is a schematic sectional drawing which shows the state from the injection start to 1st injection execution in the injection device of this invention. It is a schematic sectional drawing which shows the state in execution of the 2nd injection in the injection device of the present invention. It is a graph which shows the behavior of the plunger in the injection process performed by the injection device of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Injection apparatus 11 Heating cylinder 13 Nozzle 14 Plunger 15 Base 16 Connection member 17 1st rod 18 2nd rod 21 1st cylinder 22 2nd cylinder 30 1st drive part 31 2nd drive part 32 Control means 33 Drive means 34 Head 35 Engagement part 36 Inner hole D Air transport distance M Molten material

Claims (4)

In the injection device for injection molding by pressurizing the molten material stored in the front part of the heating cylinder inner hole with a plunger,
The injection device according to claim 1, wherein the first drive unit that drives the plunger forward is provided so as to press the plunger after rising by the forward speed of only the first drive unit and moving the flying distance.   The injection device according to claim 1, wherein a second drive unit is directly connected to the plunger.   The injection apparatus according to claim 2, wherein an output of the second drive unit is an output smaller than an output of the first drive unit.   The injection device according to claim 2, further comprising an engaging portion that moves the first driving portion forward with the idle feeding distance when the plunger is advanced by the second driving portion.

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