JP5889358B2 - Injection molding machine - Google Patents

Description

  The present invention relates to an injection molding machine capable of molding a resin containing reinforcing fibers.

Fiber reinforced resin molded articles having increased strength by containing reinforcing fibers are used for various applications. In order to obtain the molded product by injection molding, a thermoplastic resin is melted by rotation of a screw in a cylinder which is a plasticizing device, fibers are kneaded therein, and then injected into a mold of the injection molding device.
In order to obtain the effect of improving the strength by the reinforcing fibers, it is desired that the reinforcing fibers are uniformly dispersed in the resin. For this purpose, a mechanism (feeder) for forcibly supplying reinforcing fibers to the inside of a cylinder of a plasticizing device (hereinafter sometimes referred to as a plasticizing cylinder) is attached to the plasticizing cylinder (for example, patents). Document 1, Patent document 2). The feeder includes, for example, a supply cylinder and a biaxial supply screw disposed inside the supply cylinder, and the reinforcing fiber is forced from the supply cylinder to the plasticizing cylinder by rotating the screw. Supply.

JP 2000-117810 A Special table 2012-511445 gazette

However, even if the reinforcing fiber is forcibly supplied by the feeder, the reinforcing fiber may stay in the vicinity of the reinforcing fiber supply port in the supply process. If it does so, a contamination will arise by baking a reinforcing fiber, or it will become impossible to supply the reinforcing fiber by bridging stably.
The present invention has been made based on such a problem, and in an injection molding machine forcibly supplying reinforcing fibers with a feeder, it is an object to suppress the retention of reinforcing fibers in the vicinity of a reinforcing fiber supply port. And

An injection molding machine of the present invention made for such an object includes a plasticizing cylinder, a plasticizing screw provided inside the plasticizing cylinder, a resin supply unit for supplying a resin raw material into the plasticizing cylinder, and a resin A fiber supply unit that is provided on the front side of the supply unit and supplies reinforcing fibers into the plasticizing cylinder.
The fiber supply unit according to the present invention includes a supply screw that conveys the reinforcing fiber toward the plasticizing cylinder, and a supply cylinder that includes the supply screw and has a leading end communicating with the inside of the plasticizing cylinder. , the line segment L1 along the rotation axis S ₃₀₁ of the feed screw, the angle theta ₂ formed by the line segment L2 in the radial direction of the plasticizing cylinder that passes through the intersection point P1 of the outer peripheral surface of the line segment L1 and the plasticizing cylinder, the following When the rotation direction of the plasticizing screw is positive, the angle θ ₄ formed by the line segment L2 and the horizontal line when the plasticizing cylinder is viewed in front from the rotation axis direction of the plasticizing screw is satisfied. Is 45 ° or less .
−20 ° ≦ θ ₂ ≦ 45 ° (1)
In the injection molding machine of the present invention, the angle θ ₁ formed by the rotation axis S ₃₀₁ of the supply screw with respect to the direction D orthogonal to the rotation axis S ₁₀ of the plasticizing screw satisfies the following formula (2). .
0 ° ≦ θ ₁ ≦ θ _F (2)
θ _F : Lead angle of the plasticized screw flight

  In the injection molding machine of the present invention, the plasticizing cylinder includes a fiber supply port to which reinforcing fibers are supplied from a fiber supply unit, and a front edge portion of the fiber supply port is directed from the outer peripheral side to the inner peripheral side of the plasticizing cylinder. Thus, it is preferable to provide a taper cut out so that the fiber supply port is enlarged.

  ADVANTAGE OF THE INVENTION According to this invention, in the injection molding machine which supplies a reinforced fiber forcibly with a feeder, the stay of a reinforced fiber can be suppressed in the vicinity of the supply port of a reinforced fiber.

It is a figure which shows schematic structure of the injection molding machine which concerns on embodiment. It is a figure which shows the cross section of the feeder part of FIG. 1, (a) is a feeder in an advance position, (b) is a feeder in a retracted position. It is a figure which shows the plane cross section of the feeder part of the plasticizing apparatus of FIG. 1, (a) is a feeder in an advance position, (b) is a feeder in a retracted position. It is a figure explaining Formula (2). It is a figure explaining Formula (1). It is a figure which shows the preferable form of the fiber supply port of a plasticizing cylinder.

Hereinafter, the present invention will be described in detail based on embodiments shown in the accompanying drawings.
As shown in FIG. 1, the injection molding machine 1 according to the present embodiment includes a mold clamping unit 100, a plasticizing unit 200, and a control unit 50 that controls the operation of these units. The injection molding machine 1 is an apparatus that can mold a fiber reinforced resin. For this purpose, the plasticizing unit 200 includes a fiber feeder 300 that is a mechanism for supplying reinforcing fibers F.

[Clamping unit 100]
As shown in FIG. 1, the mold clamping unit 100 is fixed on the base frame 101 and fixed on the rail 107 by the operation of the fixed die plate 105 to which the fixed mold 103 is attached and the hydraulic cylinder 113. A movable die plate 111 that moves in the direction and has a movable die 109 attached thereto, and a plurality of tie bars 115 that connect the fixed die plate 105 and the movable die plate 111 are provided. The fixed die plate 105 is provided with a hydraulic cylinder 117 for mold clamping coaxially with each tie bar 115, and one end of each tie bar 115 is connected to a ram 119 of the hydraulic cylinder 117.
Each of these elements performs a necessary operation in accordance with an instruction from the control unit 50.

The general operation of the mold clamping unit 100 is as follows.
First, the movable die plate 111 is moved to the position of the two-dot chain line in the figure by the operation of the hydraulic cylinder 113 for opening and closing the mold, and the movable mold 109 is brought into contact with the fixed mold 103. Next, the male screw portion 121 of each tie bar 115 and the half nut 123 provided on the movable die plate 111 are engaged to fix the movable die plate 111 to the tie bar 115. Then, the pressure of the hydraulic oil in the hydraulic cylinder 117 is increased, and the fixed mold 103 and the movable mold 109 are tightened. After performing the mold clamping in this way, the molten resin is injected from the plasticizing unit 200 into the mold cavity to mold a molded product.
The configuration of the mold clamping unit 100 shown here is merely an example, and other configurations, for example, a toggle method or the center of the movable die plate, a clamping force is applied to clamp the fixed mold and the movable mold. It does not prevent the application or replacement of a clamping unit such as a direct pressure system.

[Plasticizing unit 200]
As shown in FIG. 1, the plasticizing unit 200 includes a cylindrical plasticizing cylinder 201, an injection nozzle 203 provided on the front side of the plasticizing cylinder 201, and a plasticizing screw provided inside the plasticizing cylinder 201. 10, a fiber feeder 300 into which reinforcing fibers F are charged, and a pellet supply hopper 207 into which resin pellets are charged. The fiber feeder 300 is provided in front of the pellet supply hopper 207. The plasticizing unit 200 includes a first electric motor 209 that moves the plasticizing screw 10 forward or backward, a second electric motor 211 that rotates the plasticizing screw 10 forward or backward, and a fiber that supplies the reinforcing fiber F to the fiber feeder 300. A supply device 213 and a pellet supply device 215 for supplying the resin pellet PP to the pellet supply hopper 207 are provided.
Each of these elements performs a necessary operation in accordance with an instruction from the control unit 50.
In the plasticizing unit 200 (injection molding machine 1) of the present embodiment, the side on which the molten resin is discharged is defined as the front, and the side on which the raw material (resin pellet PP) is supplied is defined as the rear.

The general operation of the plasticizing unit 200 is as follows.
When the plasticizing screw 10 provided inside the plasticizing cylinder 201 is rotated, the resin pellet PP made of thermoplastic resin supplied from the pellet supply hopper 207 and the reinforcing fiber F supplied from the fiber feeder 300 are Then, it is sent out to the injection nozzle 203 on the front side of the plasticizing cylinder 201. In this process, the resin pellet PP is gradually melted to become a molten resin, and after being kneaded with the reinforcing fiber F, to the cavity formed between the fixed mold 103 and the movable mold 109 of the plasticizing unit 200. A predetermined amount is injected. Needless to say, the plasticizing screw 10 undergoes a basic operation of performing injection by moving forward after the plasticizing screw 10 moves backward while receiving back pressure as the resin pellet PP melts. Further, in the present embodiment, other configurations such as a heater for melting the resin pellet PP are not applied or replaced around the plasticizing cylinder 201.
As the plasticizing screw 10, it is preferable to apply a so-called two-stage screw. In the two-stage screw, a first supply portion having a deep groove depth from the rear side, a first compression portion in which the groove depth is temporarily reduced, and a first metering portion having a shallow groove depth are continuously formed. Further, a second supply unit formed continuously at the front end of the first measuring unit directly or through a throttle unit having a smaller gap with the inner diameter of the plasticizing cylinder 201 than the first measuring unit, and a second measuring unit A second compression part and a second metering part are formed continuously with the part. When a two-stage screw is applied, the fiber feeder 300 is connected to the body portion of the plasticizing cylinder 201 corresponding to the second supply portion at the position where the plasticizing screw 10 is most advanced relative to the plasticizing cylinder 201. It is preferable to do. In the second metering unit, the molten resin pressure in the groove of the plasticizing screw 10 that has risen in the first metering unit is discharged into a space having a larger groove volume than the first metering unit deeper in the groove depth of the second supply unit. As a result, the resin pressure in the second supply section, which is the resistance back pressure for supplying the reinforcing fibers F, is reduced to about atmospheric pressure. Thereby, since the reinforced fiber F can be easily supplied from the fiber feeder 30, the effect of this invention can be acquired more notably.
In the present embodiment, the plasticizing unit 200 that also serves as an in-line type injection apparatus is shown. However, the plasticizing unit does not preclude the application or replacement of a pre-plastic type plasticizing unit.

[Fiber feeder 300]
As shown in FIGS. 2A and 3A, the fiber feeder 300 accommodates two supply screws 301 and 301 that convey the reinforcing fiber F by rotating each, and the supply screws 301 and 301. A supply cylinder 302. The two supply screws 301, 301 are accommodated inside the supply cylinder 302 side by side with their rotation axes parallel. The supply cylinder 302 includes a connection port 302a provided at the front end, a rear end wall 302b provided at the rear end, and a partition wall 302c disposed in proximity to the rear end wall 302b. In the fiber feeder 300, the side closer to the plasticizing cylinder 201 is defined as the front, and the far side is defined as the rear. Between the connection port 302a and the partition wall 302c, a first storage chamber 302d for storing the supply screws 301 and 301 is driven, and between the partition wall 302c and the rear end wall 302b, each of the supply screws 301 and 301 is driven to rotate. A second storage chamber 302e for storing the electric motors 303, 303 is provided. The drive shafts of the supply screws 301 and 301 pass through the partition wall 302c and are connected to the motors 303 and 303 in the second storage chamber 302e. The supply cylinder 302 is provided with a flange 302f on the front end side. In the supply cylinder 302, a fitting sleeve 302g on the front end side of the flange 302f is slidably fitted into a cylindrical groove provided in the fiber supply port 201a of the plasticizing cylinder 201. This is because the fiber feeder 300 is connected to the plasticizing cylinder 201 so as to be able to advance and retract. By doing so, even if the supply screw 301 is pushed backward by the molten resin pressure in the plasticizing cylinder 201 and pressed against the electric motor 303, the fiber feeder 300 to which the electric motor 303 is fixed can move backward, so the supply screw Breakage due to buckling 301 can be prevented. Furthermore, even when the fiber feeder 300 is pushed backward, the molten resin can be prevented from leaking to the outside even if the supply cylinder 302 is retracted.
In the present embodiment, the two supply screws 301 share the first storage chamber 302d. However, a partition is provided in the first storage chamber 302d so that the two supply screws 301 are stored in the respective storage chambers. May be.
Further, in this embodiment, the supply screw 301 shows two supply screws 301 of the biaxial type, but when there is no empty space for providing the biaxial fiber feeder 300 around the plasticizing cylinder 201, You may replace with the supply feeder of the single axis | shaft system of one screw.
In FIG. 2, the description of the plasticizing screw 10 is omitted.

The fiber feeder 300 includes a gantry 310 that supports a supply cylinder 302 including a supply screw 301, as shown in FIGS. 2 (a) and 3 (a). The gantry 310 includes a fixed gantry 311, a slide gantry 313 mounted on the fixed gantry 311 so as to be movable in the front-rear direction, and a plurality of coil springs 315 provided between the fixed gantry 311 and the slide gantry 313. Yes. Since the supply cylinder 302 is fixed to the upper surface of the slide mount 313, the supply cylinder 302 may move forward and backward with the slide mount 313 in the front-rear direction, that is, in the direction in which the reinforcing fiber F is supplied in the fiber feeder 300. it can.
The fiber feeder 300 includes a fiber supply hopper 305 into which the reinforcing fibers F are input. The fiber supply hopper 305 is connected to an opening 302 h provided on the upper surface of the supply cylinder 302, and the reinforcing fiber F supplied from the fiber supply device 213 is supplied into the supply cylinder 302 via the fiber supply hopper 305. The Usually, a certain amount of reinforcing fiber F is supplied from the fiber supply device 213, but even if the supply amount is changed stepwise or continuously based on the change in the rotational speed or forward / reverse speed of the plasticizing screw 10. good.

The fixed mount 311 is a flat plate-like member, and is fixed to a foundation structure not shown. Accordingly, the displacement of the fixed mount 311 is restricted including the front-rear direction. The fixed base 311 includes a spring fixing 311a formed with a rear edge protruding.
The slide mount 313 mounted on the fixed mount 311 is also a flat plate member, and its rear end is arranged with a gap from the spring fixing 311a. A coil spring 315 is disposed in the gap, and the other ends of the plurality of coil springs 315 are fixed to the rear end of the slide frame 313. When the fiber feeder 300 is installed at a predetermined position, the coil spring 315 is contracted from the free state and is disposed between the slide frame 313 and the spring fixing 311a. At this time, the amount of contraction of the coil spring 315 is determined based on the preset abnormal value of the resin pressure in the plasticizing cylinder. For example, the contraction reaction force of the coil spring 315 is set to the preset abnormal pressure determination value. The initial mounting shrinkage amount of the coil spring 315 is determined and attached so as to be equal to or less than the maximum fiber supply force value of the fiber feeder 300 obtained by integrating the cross-sectional area of the first storage chamber 302d. The supply cylinder 302 fixed to the slide mount 313 is pressed around the fiber supply port 201a of the plasticizing cylinder 201 through the flange 302f of the connection port 302a.

In the present embodiment, the fiber feeder 300 has two conditions described below.
The first condition relates to an angle θ ₂ formed by the fiber feeder 300 with respect to the plasticizing unit 200 when the injection molding machine 1 is viewed from the front, as shown in FIG. Specifically, extension of the rotating shaft _{S 301} of the feed screw 301 (line L1) is, in the radial direction of the plasticizing cylinder 201 through the intersection point _{P 1} of the outer peripheral surface of the segment _{L 1} and plasticizing cylinder 201 The angle θ ₂ formed with respect to the line segment L ₂ satisfies the expression (1). 5B shows an example of θ ₂ = 0 °, FIG. 5C shows an example of θ ₂ = 45 °, and FIG. 5D shows an example of θ ₂ = 90 °. FIG. 5E shows an example of θ ₂ = −20 °. 5A, the arrow C indicates the direction of rotation of the plasticizing screw 10, and the arrow M indicates the direction in which the molten resin flows. The origin of the angle is the line segment L ₂ , and the sign of the angle (positive / negative) is the positive (plus) direction C of rotation of the plasticizing screw 10.
−20 ° ≦ θ ₂ ≦ 90 ° (1)
When the fiber feeder 300 satisfies the formula (1), the feeding direction of the reinforcing fiber F from the fiber feeder 300 toward the plasticizing cylinder 201 is conveyed in the groove between the adjacent flights 11 of the plasticizing screw 10. The reinforcing fiber F can be put into the groove of the plasticizing screw 10 without reducing the flow rate of the molten resin to be conveyed.
The inventor makes θ ₂ in a range of −90 ° to 90 °, specifically, θ ₂ = −90 °, −45 °, −30 °, −20 °, −10 °, 0 °, 10 The amount of molten resin transported at 10 levels of °, 30 °, 45 °, and 90 °, specifically, the change in the reverse speed of the plasticizing screw 10 during the plasticizing measurement of the resin due to the rotation of the plasticizing screw 10 was measured. . As a result, change in theta ₂ in the range of formula (1), it was confirmed that the conveyance amount of the molten resin (retracting speed of the plasticizing screw 10) does not change as follows.
In the range of −20 ° ≦ θ ₂ ≦ 90 ° within the range of the formula (1), there is a difference in the retreat speed of the plasticizing screw 10 when the reinforcing fiber F is supplied into the groove of the plasticizing screw 10. There wasn't. However, when θ ₂ = −30 °, the retraction speed of the plasticizing screw 10 is reduced by 10 to 15% compared to the range of the formula (1), and when θ ₂ = −45 ° and −90 °, the molten resin becomes the fiber feeder 300. It got inside and the supply of the reinforcing fiber F became impossible.
In particular, in the case of 0 ° ≦ θ ₂ , the fiber feeder 300 (supply screw 301) does not always face upstream in the transport direction of the molten resin, so that the transport flow of the molten resin flows into the first storage chamber 302d while flowing. This can be suppressed.
In particular, when the lower limit of θ ₂ is greater than 0 °, the rotation axis of the supply screw 301 does not intersect the rotation axis of the plasticizing screw 10, so that the thrust of the supply screw 301 is applied to the plasticizing screw 10. Even in this case, the plasticizing screw 10 can be displaced in a direction perpendicular to the rotation axis direction of the supply screw 301. Thereby, there is an effect of suppressing the occurrence of early wear due to the plasticizing screw 10 being pressed against the inner surface of the plasticizing cylinder 201 on the side opposite to the supplying screw 301 by the thrust of the supplying screw 301. Further, since the rotation axis of the supply screw 301, that is, the pushing direction of the reinforcing fiber can be directed in the same direction as the conveying direction of the molten resin in the plasticizing screw 10, the reinforcing fiber F can be made to melt the resin without resisting the molten resin flow. It is possible to efficiently push the reinforcing fiber F into the molten resin flow M, and to prevent the reinforcing fiber F from staying in the vicinity of the fiber supply port 201a.
When −20 ° ≦ θ ₂ <0 °, the angle at which the conveying direction of the molten resin and the feeding direction of the reinforcing fiber F face each other is small, so the supply force of the reinforcing fiber F is equal to the resistance of the conveying flow rate of the molten resin. It seems that it was not. It should be noted that in θ ₂ = −30 °, −20 °, and −10 °, the resin in the groove of the plasticizing screw 10 just in front of the fiber supply port 201a is slightly in the fiber bundle of the reinforcing fibers F. There was a lot of impregnation of the molten resin into the fiber, and there was a tendency that the degree of fiber bundle opening of the reinforcing fibers F was large. This is because the introduction of the reinforcing fiber F slightly opposes the molten resin conveying flow, so that the reinforcing fiber F of the fiber feeder 300 is introduced into the molten resin conveying flow toward the fiber feeder 300 in the groove of the plasticizing screw 10. It seems that the pushing force is a counter force and effectively acts on the impregnation of the molten resin into the fiber bundle of the reinforcing fibers F.
Moreover, it is preferable that (theta) ₂ shall be 45 degrees or less. If greater than theta ₂ to 45 °, the fiber feeder 300 becomes to be positioned above the plasticizing cylinder 201 is heated by the electric heater (not shown), by receiving the influence of heat of the plasticizing cylinder 201, fiber In some cases, the feeder 300 may cause thermal stress, loosening of the fastening portion, malfunction of the electric system, or the like. Moreover, the heat of the part located below the fiber feeder 300 of the plasticizing cylinder 201 is covered with the fiber feeder 300 above, which may lead to heat retention and lead to overheating of the plasticizing cylinder 201 or poor temperature control. is there.
From these facts, in addition to satisfying the formula (1), θ ₂ preferably satisfies the formula (V), and more preferably satisfies the formula (W).
−20 ° ≦ θ ₂ ≦ 45 ° (V)
−10 ° ≦ θ ₂ ≦ 30 ° (W)

The second condition relates to an angle θ ₁ formed by the fiber feeder 300 with respect to the plasticizing unit 200 when the injection molding machine 1 is viewed in plan as shown in FIG. Specifically, in the fiber feeder 300, the angle θ ₁ formed by the rotation axis S ₃₀₁ of the supply screw 301 with respect to the direction D ₁₀ orthogonal to the rotation axis S ₁₀ of the plasticizing screw 10 satisfies the following formula (2). . Here, θ _F is the lead angle of the flight 11 of the plasticizing screw 10. FIG. 4B shows an example when θ ₁ adopts a value close to 0 °, and FIG. 4C shows an example when θ ₁ = θ _F is adopted.
0 ° ≦ θ ₁ ≦ θ _F (2)
When the fiber feeder 300 satisfies the expression (2), the feeding direction of the reinforcing fiber F from the fiber feeder 300 toward the plasticizing cylinder 201 is conveyed in the groove between the adjacent flights 11 of the plasticizing screw 10. Can be directed in the flow direction of the molten resin,
In particular, when the lower limit of θ ₁ is greater than 0 °, the fiber feeder 300 (supply screw 301) can always be tilted toward the rear of the plasticizing screw 10, and therefore the fiber supply port 201a (plasticizing cylinder 201). The angle θ ₃ formed by the fiber feeder 300 on the front side with the plasticizing cylinder 201 can always be an obtuse angle. Therefore, even if the plasticizing screw 10 moves forward at the time of injection, the molten resin in the groove of the plasticizing screw 10 can be prevented from entering the fiber feeder 300 by the moving force of the plasticizing screw 10. Further, by setting the upper limit value of θ ₁ to the lead angle θ _F of the flight 11, the reinforcing fiber F can be supplied to the molten resin with the wall of the flight 11 behind, so that the reinforcing fiber F is efficiently used as the molten resin. Can be pushed into.
By satisfying the expression (2), in addition to the effect of the expression (1), it is possible to suppress the reinforcing fiber F from staying in the vicinity of the fiber supply port 201a.
θ ₁ preferably satisfies the formula (X), and more preferably satisfies the formula (Y).
0 ° ≦ θ ₁ ≦ 2θ _F / 3 (X)
_{θ F / 4 ≦ θ 1 ≦} θ F / 2 ... (Y)

[Injection molding procedure]
Now, the injection molding machine 1 provided with the above elements performs injection molding in the following procedures.
In the injection molding, the resin pellet PP is heated and melted in the plasticizing cylinder 201 to be plasticized, and the plasticized molten resin is injected and filled into a cavity formed by the movable mold 109 and the fixed mold 103. A step of cooling until the molten resin filled in the cavity is solidified, and a step of opening the mold and taking out the molded product cooled and solidified in the cavity. In preparation for the next series of cycles, the mold is closed and one cycle is completed. Below, the plasticization process and injection process which this embodiment relates are demonstrated.

In the plasticizing step, the resin pellet PP is supplied from the pellet supply hopper 207 behind the plasticizing cylinder 201. At the start of plasticization, the plasticizing screw 10 is located in front of the plasticizing cylinder 201, and the plasticizing screw 10 is rotated from its initial position. By rotating the plasticizing screw 10, the resin pellet PP supplied between the plasticizing screw 10 and the plasticizing cylinder 201 is gradually melted while being heated by receiving a shearing force, and is conveyed forward. The
When the molten resin is conveyed to the fiber feeder 300, the reinforcing fiber F is supplied from the fiber feeder 300. As the plasticizing screw 10 rotates, the reinforcing fibers F are kneaded and dispersed in the molten resin, and are conveyed forward together with the molten resin. When the supply of the resin pellet PP and the reinforcing fiber F is continued and the plasticizing screw 10 is continuously rotated, the resin pellet PP and the reinforcing fiber F are conveyed to the front of the plasticizing cylinder 201 and the molten resin containing the reinforcing fiber F is discharged from the plasticizing screw 10. Stay. The plasticizing screw 10 is moved backward by the resin pressure P of the molten resin accumulated in front of the screw. When the required amount of molten resin has accumulated, the plasticizing screw 10 stops rotating and retracting.

When the injection process is started, the plasticizing screw 10 is advanced. Then, the pressure of the molten resin (resin pressure) accumulated in front of the plasticizing screw 10 is increased, and the molten resin is injected from the injection nozzle 203 toward the cavity.
It is preferable to supply the reinforcing fiber F from the fiber feeder 300 and the resin pellet PP from the pellet supply hopper 207 during the injection process.

[Effect]
Next, the effect of this embodiment, especially the effect by the fiber feeder 300 will be described.
When the fiber feeder 300 satisfies the formula (1) and further satisfies the formula (2), the reinforced fiber F is plasticized screw without reducing the transport flow rate of the molten resin transported in the plasticizing screw 10. It can be put into 10 grooves. Furthermore, since the reinforced fibers F to be input can easily be placed on the flow of the molten resin, and the reinforced fibers F can be prevented from staying in the vicinity of the fiber supply port 201a, the injection molding machine 1 of the present embodiment has a molding failure. Can be prevented.

  Next, the supply cylinder 302 is supported by a slide frame 313 in which the supply cylinder 302 is supported by a coil spring 315. Therefore, in the plasticizing process and the injection process, even if the resin pressure P increases and the molten resin pushes the supply cylinder 302 backward, as shown in FIGS. 2 (b) and 3 (b) The cylinder 302 can be retracted without difficulty. That is, the frame 310 of the fiber feeder 300, particularly the coil spring 315, functions as a safety device against an abnormal increase in resin pressure.

The preferred embodiments of the present invention have been described above. However, the configurations described in the above embodiments can be selected or changed to other configurations as appropriate without departing from the gist of the present invention.
For example, as shown in FIG. 6, the front edge portion of the fiber supply port 201a is cut out so that the fiber supply port 201a expands from the outer peripheral side of the plasticizing cylinder 201 to the inner peripheral side, thereby providing a taper 201b. be able to. By providing this taper 201b, the following effects are produced. In FIG. 6, the same components as those in FIG. 2 are denoted by the same reference numerals as those in FIG.
When the plasticizing screw 10 advances for injection, the reinforcing fibers F in the vicinity of the inner peripheral surface of the plasticizing cylinder 201 in the fiber supply port 201a are dragged inward of the plasticizing cylinder 201 along the taper 201b. It becomes easy to be caught. Therefore, by providing the taper 201b, it is possible to prevent the reinforcing fibers F from staying in the vicinity of the fiber supply port 201a.

  Moreover, it is desirable that the injection molding machine according to the present invention satisfies the following formula (7). This expression (7) is intended to separate the plasticizing cylinder 201 from the supply screw 301 (tip) by a predetermined distance represented as the fiber filling distance L. The fiber filling distance L is calculated based on the bulk density and angle of repose of the reinforcing fiber F. Bulk density and angle of repose vary depending on fiber length and fiber type.

L> L0 × α (7)
L: Fiber filling distance L ₀ : Fiber filling length (from supply hopper center to cylinder wall)
D: Fiber supply feeder cylinder diameter

It is preferable to satisfy the formula (7) for the following reason.
When the injection molding machine is operating normally, the molten resin in one flight of the plasticizing screw is in an unfilled state and there are voids. The voids are filled with reinforcing fibers F and dispersed in the resin. However, if a pressure abnormality occurs in the plasticizing cylinder, the molten resin will be filled more than normal, so the pressure in the plasticizing cylinder will rise and the resin will flow back to the fiber supply section, which is the low pressure section. This phenomenon occurs. Therefore, an attempt is made to provide a fiber filling distance L that can cope with vent-up.

DESCRIPTION OF SYMBOLS 1 Injection molding machine 10 Plasticization screw 50 Control part 100 Clamping unit 101 Base frame 103 Fixed mold 105 Fixed die plate 107 Rail 109 Movable mold 111 Movable die plate 113 Hydraulic cylinder 115 Tie bar 117 Hydraulic cylinder 119 Ram 121 Male thread part 123 Half nut 200 Plasticizing unit 201 Plasticizing cylinder 201a Fiber supply port 203 Injection nozzle 207 Pellet supply hopper 209 First motor 211 Second motor 213 Fiber supply device 215 Pellet supply device 300 Fiber feeder 301 Supply screw 302 Supply cylinder 302a Connection port 302b Rear end wall 302c Partition wall 302d First storage chamber 302e Second storage chamber 302f Flange 302g Fitting sleeve 303 Electric motor 305 Fiber supply hopper 310 Mounting base 311 Gantry 311a spring fixing 313 slide platform 315 coil spring

Claims (4)

A plasticizing cylinder;
A plasticizing screw provided inside the plasticizing cylinder;
A resin supply section for supplying a resin raw material into the plasticizing cylinder;
A fiber supply unit that is provided on the front side of the resin supply unit and supplies reinforcing fibers into the plasticizing cylinder;
The fiber supply unit is
A supply screw for conveying the reinforcing fibers toward the plasticizing cylinder;
A supply cylinder in which the supply screw is housed and the tip side communicates with the inside of the plasticizing cylinder, and
The fiber supply unit is
Wherein the line segment L1 along the rotation axis S ₃₀₁ of the feed screw, the angle theta ₂ formed by the plasticizing radial line L2 of the cylinder through the intersection P1 of the outer peripheral surface of the plasticizing cylinder with the line segment L1 is In addition to satisfying the following formula (1) ,
When the direction of rotation of the plasticizing screw with a positive angle theta ₄ is at 45 ° or less formed by the horizontal line when the rotational axis direction of the plasticizing screw and the line segment L2 is viewed from the front of the plasticizing cylinder ,
An injection molding machine characterized by that.
−20 ° ≦ θ ₂ ≦ 45 ° (1) The fiber supply unit is
An angle θ ₁ formed by the rotation axis S _{301 of the} supply screw with respect to a direction D perpendicular to the rotation axis S ₁₀ of the plasticizing screw satisfies the following formula (1):
Injection molding machine according to claim 1.
0 ° ≦ θ ₁ ≦ θ _F (1)
θ _F : Lead angle of the plasticized screw flight The plasticizing cylinder includes a fiber supply port through which the reinforcing fiber is supplied from the fiber supply unit,
A leading edge portion of said fiber supply port, toward the outer side of the plasticizing cylinder, comprising a taper that the fiber supply opening is cut out so as to expand,
The injection molding machine according to claim 1 or 2. The fiber supply unit is
Comprising two said supply screws,
The injection molding machine according to any one of claims 1 to 3.

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