JP2006334974A - Injection device of liquid resin molding machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an injection device of a liquid resin molding machine which mixes the liquid resin uniformly, finely, and quickly to inject the liquid resin while saving the mixed liquid to be discarded after the stop of operation. <P>SOLUTION: In the injection device 1 of the liquid resin molding machine equipped with a supply device 10 supplying the liquid resin in a prescribed ratio, a mixer 20 mixing the liquid resin, and a plunger injection device 50 which weighs the mixed liquid resin and injects it, the mixer 20 has a mixing shaft 22 which is rotated in a mixing cylinder 21 and moved forward/backward, a rotation driving device 30 which controls the intensity of the mixing by controlling the rotation of the shaft, and a backflow preventing mechanism preventing the backflow of the mixed liquid by controlling the forward/backward movement of the shaft. Moreover, the mixing shaft has innumerable projections 22b in its major portions. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an injection apparatus for a liquid resin molding machine in which at least two kinds of liquid resins are mixed at a constant ratio, and the mixed liquid is injected into a high-temperature mold and molded, and in particular, the liquid resin is mixed. The present invention relates to an injection apparatus for a liquid resin molding machine having characteristics.

  Liquid resin molding is typically referred to as LIM (LIQUID INJECTION MOLDING), and is used, for example, for molding LSR (liquid silicone rubber) and silicon lenses. In this type of molding, a liquid resin that is liquid at normal temperature, for example, a two-component resin consisting of a main agent and a curing agent, is used and is mixed in a certain ratio and then filled into a high-temperature mold to form a molded product. become. An injection device for such molding includes a supply device that supplies at least two kinds of liquid resins at a predetermined ratio, a mixing device that mixes these liquid resins, and injects or injects the mixed liquid into a mold. And an injection device. The liquid resin is kept at room temperature or below until it is injected into the mold cavity.

  More specifically, this type of injection device is disclosed on the following homepage that can be browsed on the Internet, or on the following utility model registration application or patent application.

  For example, on the Internet website http://www.sanjo.co.jp/business/liquid.html (created by Yamashiro Seiki Seisakusho Co., Ltd.), practical technologies and equipment for liquid resin molding machines are disclosed in detail. Has been.

  In addition, Japanese Utility Model Publication No. 3-20092 discloses an injection apparatus that mixes a plurality of stock solutions immediately before injecting them into a mold. More specifically, the injection device includes at least two stock solution tanks, two metering cylinders including a piston, one mixing device including an injection nozzle, and a mixing unit communicating the metering cylinder and the mixing device. including. The mixing device is illustrated as a device like a static mixer in which the mixing member is statically fixed in the tube. In such an injection device, the measuring cylinder measures the two stock solutions from the stock solution tank, the piston of the metering cylinder presses the two stock solutions and supplies them to the mixing device via the mixing section, and the mixing device mixes the two stock solutions. The mixed solution is injected. The raw material 2 liquid is divided and subdivided by a mixing member and mixed.

  Japanese Patent Application Laid-Open No. 6-63992 discloses an injection apparatus that mixes at least two liquids with a screw. More specifically, the injection device includes two resin tanks that store at least two liquids, one mixing and stirring cylinder that includes a screw, and two measuring cylinders that communicate with the resin tank and the mixing and stirring cylinder. . Such an injection apparatus first measures a predetermined amount of each liquid resin individually with a measuring cylinder, and then supplies them to a mixing and stirring cylinder at a predetermined mixing ratio. The injection device mixes and measures the two liquids by retreating the screw in the cylinder while rotating, and finally injects a predetermined amount of the liquid mixture by the advance of the screw. The mixing apparatus of this apparatus measures and injects the liquid resin with a screw that moves backward and forward like an inline injection molding machine.

  Japanese Patent Application Laid-Open No. 2000-61992 discloses an injection device having a basic configuration of a screw preplar type injection device. This apparatus includes premixing means such as a static mixer, main mixing means corresponding to a preplasticizer of a screw preplar type injection apparatus, and an injection apparatus having a configuration similar to a plunger injection apparatus. More specifically, the injection device includes two raw material storage tanks that store at least two liquids, a weighing unit that measures the two liquids from the raw material storage tanks at a predetermined ratio, a premixing unit including a static mixer, and the like. Main mixing means including a mixing screw corresponding to the pre-plus screw. In this injection device, the resin is once mixed by the premixing means, then further mixed by the main mixing means, and the mixed liquid is measured by the plunger unique to the present invention and then injected. However, there is no special explanation about the screw of this device. Regarding mixing, it is described that both preliminary mixing using a static mixer or the like and main mixing using a screw are performed.

  The mixing ratio of the two liquids in the injection apparatus as described above is usually 1: 1. The limit of the mixing ratio when one of the liquids has a particularly small biased ratio is practically about 10: 1. For the viscosity, a combination of the same viscosity ratio is selected. The reason why such a combination of the mixing ratio and the viscosity ratio is employed is to realize uniform and refined mixing at an accurate ratio.

Internet homepage http://www.sanjo.co.jp/business/liquid.html Japanese Utility Model Publication No. 3-20092 (Fig. 1) Japanese Patent Laid-Open No. 6-63992 (FIGS. 1 and 2) Japanese Patent Laid-Open No. 2000-61992 (FIG. 1)

  However, the injection apparatus as described above does not strictly realize uniform and fine mixing at an accurate mixing ratio. Moreover, the injection device does not realize quick mixing and quick injection after mixing.

  Originally, in mixing in a molding machine, it is required that at least two liquids are accurately mixed at a predetermined ratio, and of course, uniformly and finely mixed. And in the measurement process or injection process performed intermittently, the mixed state should not vary immediately after the start of the process and immediately before the end of the process. Moreover, the mixing of the liquid resin once started must be completed in a short time and in a short route as much as possible. In addition, it is desirable that the combination of liquid resins is not restricted as much as possible by the difference in mixing ratio and viscosity between the two.

  However, the conventional injection device does not sufficiently meet the above requirements in a strict sense. For example, in a static mixer, a high viscosity liquid resin and a low viscosity liquid resin may not be sufficiently mixed. In particular, mixing of two liquids having a large viscosity difference tends to be insufficiently mixed in a strict sense. In addition, a difference in flow velocity tends to occur between the inlet and the outlet of the pipeline. The flow rate difference between the two liquids causes the mixing ratio immediately after the start of mixing and the mixing ratio immediately before the end to gradually vary in a strict sense, and in an extreme case, liquid resin feed unevenness occurs to vary the mixing ratio. On the other hand, even when the two liquids are too low in viscosity, the two liquids in the pipe may flow too laminarly, resulting in insufficient mixing.

  Of course, increasing the length of the static mixer tube is already at its limit. In addition, the number of mixing members provided in the mixer tube is limited because it is cascaded. In addition to the ease of use of this apparatus, it is necessary to consider shortening of the mixing time and shortening of the route of the mixture.

  Inadequate mixing also exists strictly in mixing with conventional screws. Originally, a screw groove of an injection molding machine is a deep and simple groove because it heats a pellet-shaped resin material. Therefore, the screw is not suitable for mixing liquid resin. This problem is particularly noticeable when the viscosity of the two liquids is low.

  In addition, the in-line screw molding machine has various problems due to the behavior of the check ring attached to the screw head. In addition, in a conventional screw pre-plastic molding machine, simplification around a backflow prevention mechanism that prevents backflow of resin from the injection device to the plasticizing device is desired. This is because the mixed liquid resin is liable to stay around the backflow prevention site and eventually produce a solidified product. In particular, the problem increases when there is a moving object in the backflow prevention mechanism.

  In particular, in the embodiment of Patent Document 3, a static mixer is combined to make up for the shortage of mixing by the screw. In this case, the mixing path becomes longer and the mixing time also becomes longer. Therefore, the number of sections that must be cleaned when molding is stopped or when the molding resin is changed increases, increasing the maintenance burden. In addition, the amount of resin discarded by washing increases, resulting in increased cost waste.

  In addition, when two liquids are mixed at an unbalanced mixing ratio in which the amount of one liquid is particularly small, the physical properties of the liquid mixture tend to vary if the mixing is insufficient. This is because the smaller amount of liquid resin (for example, an additive) exhibits its effects only when it is accurately mixed in a predetermined small ratio. In this case, for example, if the additive is a curing agent, the curing rate of the mixed solution varies and the molding cycle is disturbed. In extreme cases, the cure may be significantly delayed or begin to cure in the injection device. This phenomenon becomes more prominent when the liquid mixture is not ejected quickly or when the path through which the liquid mixture passes has a complicated shape. Further, when such mixing corresponds to the molding of a two-component lens, not only the molding cycle is disturbed but also the physical properties of the molded product, for example, the refractive index of the lens is not uniform.

  In order to solve the above problems, it is effective to strengthen the mixing of the two liquids from the start of mixing and to change the strength. And it is desirable to reduce the path | route in which a liquid mixture exists, and to simplify in shape. As a result, mixing can be performed in a wide range of combinations of uneven mixing ratios or different viscosities.

  Accordingly, the present invention provides an injection apparatus for a liquid resin molding machine that performs mixing more precisely and more finely and more quickly than before by efficiently mixing liquid resin and shortening and simplifying the mixing path as much as possible. suggest. In addition, the present invention proposes a mixing method in which the mixing strength of the liquid resin can be adjusted to be variable using the mixing device of the injection device of the present invention.

In order to solve the above problems, an injection device for a liquid resin molding machine of the present invention is:
A supply device (10) for supplying at least two kinds of liquid resins at a predetermined ratio, a mixing device (20) for mixing the supplied liquid resins, and sending the mixed liquid resin to the plunger injection device (50) For this purpose, the communicating member (39) for communicating the mixing device and the plunger injection device, and the liquid mixture of the liquid resin is once measured by the injection cylinder (51) by the retreat control of the plunger (52), and then the plunger is advanced. A plunger injection device (50) for injecting the liquid mixture under control, and an injection device (1) for a liquid resin molding machine,
The mixing device rotates or moves back and forth in a mixing cylinder (21) communicating with the supply device via a material supply hole (21b), and a cylinder hole (21a) of the mixing cylinder, and most of the mixing cylinder (21) A mixing shaft (22) having innumerable convex protrusions (22b) on the side surface thereof, a rotation drive device (30) for controlling the intensity of mixing by controlling the rotation of the mixing shaft, and the longitudinal movement of the mixing shaft And a backflow prevention mechanism (40) for preventing backflow of the mixed solution.

  Further, the convex protrusion of the mixing axis of the present invention is preferably formed so as to be partitioned by a plurality of intersecting spiral grooves (22e) cut so as to cross each other along the mixing axis.

  In addition, the mixing shaft of the present invention has the convex protrusions in the majority thereof, and further has a double-striped short-pitch spiral groove (22c) in the vicinity of a desired portion of the material supply hole, It is preferable that the twist direction is inclined so that the liquid resin is fed from the base side to the tip side when the mixing shaft rotates.

  Further, the communication hole (39a) of the communication member of the injection device of the present invention and the cylinder hole (51a) of the injection cylinder are opened at the end surface (55b) of the cylinder hole of the injection cylinder. It is good to communicate with each other.

  In addition, the adjustment of the mixing strength of the liquid resin in the injection device of the present invention may be performed by adjusting the rotational speed control of the mixing shaft and the retreat speed control of the plunger in a correlated manner.

  In addition, the code | symbol in the said parenthesis refers to the component contained in drawing, and does not limit them only to the thing of drawing.

  According to the injection apparatus of the liquid resin molding machine of the present invention, the mixing device includes a mixing shaft whose rotation is controlled, and the mixing shaft is provided with innumerable convex protrusions on the majority thereof. Therefore, the liquid resin supplied from the supply device at an accurate mixing ratio is uniformly and finely and rapidly mixed by countless convex protrusions whose rotation is controlled, and is measured by the plunger injection device. The mixing strength of the injection device can be adjusted by controlling the rotation speed of the mixing shaft in accordance with the combination of liquid resins. In addition, this injection device has a huge number of convex protrusions on the mixing shaft, enabling the shaft length to be shortened, reducing the amount of liquid that has already been mixed, and discarding when stopping operation or changing the resin. The amount of resin used can be reduced. As a result, the mixing shaft can be easily cleaned and the maintainability is improved.

  Further, the convex protrusions of the mixing shaft of the present invention are formed so as to be finely divided by a plurality of spiral grooves intersecting each other along the mixing axis, and a huge number is formed in the length direction thereof. . Therefore, the liquid resin in the mixing cylinder is substantially divided into two by adjacent convex protrusions, and is further divided into enormous times while being sent along the mixing cylinder. As a result, uniform and fine mixing is performed more quickly. In addition, since the groove shape is shallow and simple and orderly, it is easy to clean the mixed liquid performed at the end of molding or resting.

  Further, the mixing shaft of the present invention has a double grooved short pitch spiral groove in the vicinity of the material supply hole. Therefore, the liquid resin supplied from the supply device is not forced to be sent forward by the spiral groove whose rotation is controlled, and no stagnation occurs in the vicinity thereof.

  Further, since the communication hole of the present invention communicates with the end face of the cylinder hole of the injection cylinder, the mixed liquid flows simply and naturally. As a result, the phenomenon that the mixed liquid stays in the vicinity of the end face of the cylinder hole and solidifies can be suppressed.

  Further, according to the method of mixing the liquid resin in the injection device of the present invention, the injection device controls the retraction speed of the plunger together with the rotation speed control of the mixing shaft, and adjusts them in a correlated manner. Therefore, the mixing method of the present invention can adjust the mixing strength of the liquid resin over a wide range according to the mixing ratio or viscosity difference of the liquid resin, and can select a wider range of liquid resin combinations. To.

  As shown in FIGS. 1 and 2, the injection device 1 of the liquid resin molding machine includes a supply device 10 that supplies at least two types of liquid resin materials (raw solutions), a mixing device 20, and a plunger injection device 50. The basic configuration will be described first.

  The supply device 10 is the same as a conventional stock solution supply device. The apparatus 10 supplies at least two types of stock solutions to the downstream mixing apparatus 20. The two stock solutions, and in some cases the three stock solutions containing a colorant (pigment) are supplied in a pail can or drum can (not shown). The supply device 10 includes, for example, a material replenishing device 12 and a feeding device 13. The former carries a pail can and the like so as to be replaceable, and supplies the stock solution to the feeding device 13 from them. Is temporarily stored and then fed to the mixing device 20 at a predetermined mixing ratio.

  The mixing device 20 is the device that most includes the features of the present invention. The description will be given below, but before that, the downstream communication member 39 and the plunger injection device 50 will be described first.

  The communicating member 39 is a member that communicates the mixing cylinder 21 of the mixing device 20 with the injection cylinder 51 of the plunger injection device 50 described next. The communication hole 39a in the communication member 39 is a simple circular hole.

  The plunger injection device 50 is equivalent to the plunger injection device included in the conventional pre-plastic injection device. The injection device 50 includes an injection cylinder 51 in which a cylinder hole 51a is formed, a plunger 52 that moves forward and backward therein, a plunger drive device 53 that drives and controls the forward and backward movement of the plunger 52, and a gold not shown. It includes a nozzle 54 that abuts the mold, and a nozzle adapter 55 that couples the nozzle 54 and the tip of the injection cylinder 51. The plunger driving device 53 may be either an electric type or a hydraulic type. The cylinder hole 51a communicates with the nozzle hole 54a through the through hole 55a of the nozzle adapter 55, and communicates with a mold cavity (not shown). The cylinder hole 51a communicates with the communication hole 39a of the communication member 39 through the surface 55b with the concave surface formed in the nozzle adapter 55 as a terminal surface 55b. Further, the outer circumferences of the nozzle 54 and the injection cylinder 51 are cooled by cooling pipes 56 and 57. The plunger injection device 50 includes a position detection device such as a conventionally known linear scale (not shown) that detects the position of the plunger 52, and sends the position to a control device (not shown).

  A mixing device 20 that best includes the features of the present invention is shown in FIGS. The mixing device 20 includes a mixing cylinder 21 in which a cylinder hole 21a is formed, a mixing shaft 22 that rotates or moves back and forth therein, a rotary drive device 30 that rotates the shaft 22, and a shaft that moves back and forth. An axial drive device 24. The mixing device 20 is provided with at least two material supply holes 21b and 21c (hereinafter represented by 21b) in the vicinity of the base portion of the cylinder 21, from which the feeding device 13 of the supply device 10 is provided. Communicate. Such a mixing cylinder 21 is cooled in the same manner as the injection cylinder 51 described above.

  The mixing shaft 22 has a tip surface 22a formed in a substantially conical shape. The mixing shaft 22 has innumerable convex protrusions 22b, which will be described in more detail in the embodiment, in the most part from the base portion of the conical tip surface 22a to the vicinity of the material supply hole 21b. The mixing shaft 22 has a spiral groove 22c that can be omitted in some embodiments. Although described in detail in the embodiment, the spiral groove 22c is formed in the vicinity of the position facing the material supply hole 21b. The mixing shaft 22 is held by a bearing 25 so as to rotate in the mixing cylinder 21. Further, the mixing shaft 22 has a slide groove 22 d composed of a plurality of grooves that allow axial movement with respect to the bearing 25. The proximal end side of the mixing shaft 22 is fixed to the output shaft of the axial drive device 24. The mixing shaft 22 is coupled to the pulley 26 at a position close to the base end. A compression coil spring 27 is mounted between the pulley 26 and the bearing 25 to press them in a direction away from them.

  The downstream end surface of the cylinder hole 21a of the mixing cylinder 21 is formed in a shape that comes into contact with no gap when the conical tip surface 22a of the mixing shaft 22 moves forward. This end surface functions as a seal seat surface 21d for preventing a backflow described later.

  The rotation drive device 30 is a device that includes a rotation motor 31, a pulley 32 attached to the output shaft thereof, a timing belt 33, and a pulley 26 on the mixing shaft 22. These components rotate the mixing shaft 22 when the stock solution is mixed and supplied to the plunger injection device 50, that is, when the mixture is measured. The rotational speed of the rotary motor 31 is detected and fed back by a conventionally known encoder (not shown). The rotational speed of the mixing shaft 22 is controlled to the set rotational speed. Therefore, the intensity of mixing by the mixing shaft 22 can be adjusted by setting the rotation speed according to the viscosity of the stock solution to be mixed. A more detailed description of mixing and metering is further detailed in the examples.

  The axial drive device 24 releases the thrust on the mixing shaft 22 when measuring, and advances the mixing shaft 22 when injecting. In the former measurement, the coil spring 27 moves the pulley 26 backward toward the base end side of the mixing shaft 22, so that the front end surface 22 a of the mixing shaft 22 is separated from the seal seat surface 21 d at the end of the cylinder hole. Thus, the mixing cylinder 21 and the injection cylinder 51 communicate with each other, and the liquid mixture in the mixing cylinder 21 moves to the injection cylinder 51 side for measurement. The movement of the undiluted solution at this time mainly depends on the suction force due to the retraction of the plunger 52, and as a result depends on the feeding pressure that the mixed solution receives from the feeding device 13. On the other hand, in the latter injection, the axial drive device 24 advances the mixing shaft 22 against the coil spring 27. Therefore, the axial drive device 24 presses the conical tip surface 22a of the mixing shaft 22 against the seal seat surface 21d to prevent the backflow of the liquid mixture from the plunger drive device 53 to the mixing cylinder 21 side. Thus, the combination of the mixing shaft 22, the axial drive device 24, the spring 27, and the conical tip surface 22a and the seal seat surface 21d constitutes a backflow prevention mechanism 40 having a simple configuration.

  Hereinafter, a more specific description of the main components will be described in detail together with examples.

  First, a conventionally known configuration of the supply device 10 will be supplementarily described. The material replenishing device 12 includes a pump (not shown) that replenishes the stock solution from a pail can or the like to the feeding device 13. The feeding device 13 includes, for example, a feeding cylinder 15 having a cross-sectional area matched to the mixing ratio of the stock solution, a piston 16 and a driving device (not shown) for driving the piston. Repeated storage and pumping downstream. The set of the feeding cylinder 15 and the piston 16 is combined so as to be exchangeable in accordance with the mixing ratio of the stock solution. The forward and backward positions of the piston 16 are detected by, for example, a limit switch or the like (not shown), and are recognized by the control device as the volume of the stock solution in the feed cylinder 15. The material replenishing device 12 and the feeding device 13 are communicated with each other via, for example, a three-way valve 18, and they are communicated with the mixing device 20 through piping.

  In the supply device 10 described above, when the decrease in the stock solution in the feeding device 13 is detected by the limit switch, the material replenishing device 12 operates to replenish the feeding device 13 with the stock solution. When the completion of replenishment is detected by the limit switch, the material replenishing device 12 stops and the communication between the material replenishing device 12 and the feeding device 13 is blocked by the three-way valve 18. Thereafter, the feeding device 13 pushes the stock solution from the feeding cylinder 15 and feeds it to the mixing cylinder 21 every time it is weighed.

  Of course, the supply device 10 is not limited to the illustrated embodiment described above. Any device may be used as long as it can set and control the feeding amount in accordance with the mixing ratio of the supplied stock solution. Of course, there is no need to separate the material replenishing device 12 and the material feeding device 13, and it is not necessary to set the mixing ratio based on the area ratio of the two cylinders. These may be replaced by individual discharge control of the pump.

  Next, the mixing shaft 22 of the mixing device 20 will be described in detail. The innumerable convex protrusions 22b formed on most of the mixing shaft 22 are formed to be finely divided by a plurality of spiral grooves 22e cut so as to intersect with each other along the mixing shaft 22. The More specifically, the grooves are formed such that the groove width is 2 mm to 5 mm, the distance between the grooves is about 4 mm to 8 mm, and the depth of the groove is 1 mm to 3 mm. Here, the shape having a groove interval of 5 mm, for example, is a shape in which four spiral grooves 22e are formed at a pitch of 20 mm. For example, on the mixing shaft 22 having a nominal outer diameter of 22 mm and an outer diameter of 21.6 mm, four spiral grooves 22e having a groove width of about 3 mm and a groove depth of about 1.5 mm are formed at a pitch of 20 mm. And another set of spiral grooves 22e having the opposite twisting direction are formed so as to intersect with each other. Such grooves are formed in the axial direction about 20 times (one pitch is equivalent to 5 pitches of 4 spirals). Thus, the spiral grooves are formed as intersecting spiral grooves 22e so that the distance between the grooves is about 5 mm. The convex protrusions 22b are rhombus-shaped fine and low-profile protrusions having a width of about 2 mm. The number of the protrusions 22b is eight around one and about 20 in the axial direction. However, eight protrusions around one point indicate a total of eight protrusions that circulate in two rows of four in a zigzag manner.

  When the spiral groove 22c having multiple short pitches is formed on the mixing shaft 22, the convex protrusion 22b is naturally formed on most of the mixing shaft 22 excluding the spiral groove 22c. On the other hand, when the spiral groove 22 c is not formed, the convex protrusion 22 b is formed over almost the entire length of the mixing shaft 22. In the former case, it is used when the mixed liquid is easily cured when it stays. This is because the retention preventing action of the spiral groove 22c having a multiple short pitch described below can be expected. On the other hand, the latter case is employed when the mixed solution does not harden very much or when hardening of the mixed solution on the base end side from the material supply hole 21b does not cause any particular problem. In this latter case, the spiral machining is simplified to the extent that the machining of the spiral groove 22c is unnecessary.

  The spiral groove 22c of the mixing shaft 22 in the vicinity of the material supply hole 21b is processed as an extension of one groove processing of the intersecting spiral groove 22e for convenience of processing. For example, in the mixed shaft having a nominal outer diameter of 22 mm as described above, four grooves are formed at a pitch of 20 mm, similar to the spiral groove 22e, and such grooves are formed for one pitch, that is, about four turns. Is done. Further, the twist direction is inclined in a direction in which the stock solution is sent from the base side to the tip side when the shaft rotates. For example, when the shaft rotates clockwise as viewed from the distal end side, the twisting direction of the spiral is the right-handed screw direction. Such a spiral groove 22c pushes the stock solution supplied from the material supply hole 21b to the distal end side, thereby preventing the liquid mixture from staying on the proximal end side from the hole 21b. The fact that the spiral grooves 22c are described as having a short pitch means that they have a short pitch when compared with a conventional screw.

  The slide groove 22d formed at the position facing the bearing 25 is a plurality of short pitch shallow groove annular grooves. The slide groove 22d accumulates grease or the like in the groove, and enables the axial movement while the mixing shaft 22 is held by the bearing 25.

  In the illustrated example in which both the convex protrusion 22b and the double spiral groove 22c are machined into the mixing shaft 22, a clearance machining groove 22f for machining one of the machining of the intersecting spiral groove 22e is machined between them. . Although this relief machining groove 22f is likely to cause the stock solution to stay, it does not. This is because the undiluted solution moves forward without staying in this portion by the action of sucking the undiluted solution due to the retraction of the plunger 52 at the time of metering or the pressure feeding operation of the undiluted solution by the feeding device 13. When the spiral groove 22c having multiple short pitches is formed, the groove is also useful for preventing retention.

  The mixing shaft 22 has a large-diameter portion 22g having a larger outer diameter at the end of the spiral groove 22c. And the seal packing 28 is being fixed to the mixing cylinder 21 side so that it may contact | abut to this part 22g. The seal packing 28 prevents the stock solution from leaking from the rear end of the cylinder 21.

  In the injection apparatus 1 configured as described above, the supply apparatus 10 supplies at least two stock solutions to the mixing apparatus 20 accurately at a predetermined ratio during measurement. The stock solution is pressurized to about 0.5 MPa to 8 MPa and fed into the mixing cylinder 21 from the material supply hole 21b.

  Next, the mixing device 20 mixes the stock solution by the rotation of the mixing shaft 22 in the same way of measurement. Mixing is performed as follows.

When the mixing shaft 22 rotates, the stock solution is roughly divided into two by the adjacent convex protrusions 22b. For example, if the above-mentioned nominal outside diameter of 22mm, the convex projection 22b is approximately 2 ^eight divided during one revolution since there eight around one axis 22 is performed. Such division is performed on most of the mixing shaft 22. So, when the stock solution during one rotation of the shaft is fed one rotation of the convex projection 22b (2 columns in a zigzag 8) is about 2 ^eight split lines in 20 laps of minute projections After all, the division is performed an enormous number of times reaching ^{28 × 20} times. In the case of two rounds, it is ^{28 × 10} . This number of divisions is not a ratio of the number of divisions of the conventional static mixer, even if it is a conservative number. Thus, the mixing of the stock solution is sufficiently refined and uniformized. In addition, the mixing is carried out promptly since it starts strongly from immediately after the start. Therefore, the length of the mixing shaft 22 can be shortened more than the conventional screw and further reduced from the 20 rounds.

  In the injection device 1 of the present invention, the mixing strength can be adjusted widely. The mixing device 20 and the plunger injection device 50 cooperate to adjust the rotational speed of the mixing shaft 22 and the retreating speed of the plunger 52 in a correlated manner, whereby the mixing strength of the stock solution can be controlled. . That is, the degree of mixing can be increased by increasing the rotational speed and decreasing the reverse speed, and the mixing speed can be increased by decreasing the rotational speed and increasing the reverse speed. Therefore, in the injection device 1 of the present invention, the former mixing condition is adopted when the mixed liquid is difficult to mix, and the latter mixing condition is adopted when the mixed liquid is easy to mix, thereby reducing the mixing fineness and mixing. It is possible to select which speed is to be prioritized.

  In addition, even in the measurement where mixing is performed intermittently, the mixing ratio at the start of measurement and the mixing ratio at the end of measurement hardly vary. As described above, since the undiluted solution is frequently divided immediately after the start of the rotation of the mixing shaft 22, uniform refinement of the mixing is performed without being greatly affected by the difference in viscosity between the two solutions. .

  The stock solution in the mixing cylinder 21 mixed as described above is sent to the plunger injection device 50 simultaneously with the end of mixing. Then, one shot of the mixed liquid necessary for injection is measured by the injection cylinder 51. When the weighing is completed, the plunger injection device 50 stands by until the next injection timing. During this time, the axial drive device 24 operates the backflow prevention mechanism 40 to advance the mixing shaft 22 to prevent backflow.

  When the injection timing is reached, the plunger injection device 50 advances the plunger 52 to inject (inject) the mixed solution into the mold cavity. At this time, the backflow prevention mechanism 40 prevents the stock solution whose pressure has increased in the injection cylinder 51 from flowing back into the mixing cylinder 21.

  The reaction of the mixed liquid injected into the mold by injection is accelerated by the heat of the mold under heat control, and is solidified according to the shape of the cavity to become a molded product. During this reaction time, the backflow prevention mechanism 40 moves the mixing shaft 22 backward to connect the mixing cylinder 21 to the injection cylinder 51. Then, the next measurement is performed in the same manner as described above. Thus, a series of molding is completed.

  According to the injection device 1 of the present invention, the stagnation of the mixed liquid is also suppressed. This is because the path through which the liquid mixture passes is shorter than that of the prior art, and the shape of the path is relatively simple. More specifically, the shortening of the mixing shaft 22 as described above can be achieved, and the shape constituted by the convex protrusions 22b and the intersecting spiral grooves 22e seems to be complicated at first glance, but the shallow grooves are orderly, The communication hole 39a of the communication member 39 is only a simple circular hole and does not include a movable object for preventing backflow on the way, and the conical tip surface 22a of the mixing shaft 22 and the seal seat for preventing backflow during injection This is because the combination with the surface 21d is simple and does not include a movable object, and the plunger 52 approaches to such a degree that it almost comes into contact with the end surface 55b of the cylinder hole 51a when injection is completed.

  In particular, since the communication hole 39a of the communication member 39 communicates with the injection cylinder 51 at the end surface 55b of the cylinder hole 51a, the mixed liquid can be simply and naturally from the communication hole 39a to the cylinder hole 51a and the nozzle hole 54a. Flowing. Therefore, in the injection device of the present invention, the phenomenon that the mixed liquid stays at the end surface 55b of the cylinder hole 51a and solidifies, which has been a particular problem in the molding of the liquid resin, is suppressed. As a result, the volume of the cylinder hole 51a is reduced. As a result, there is almost no phenomenon that the molded product is short shot.

  The shortness of the mixing path and the simplicity of the path shape are convenient for removing the mixed solution after molding. This is because not only the time loss of the purge is suppressed, but also the discarded materials are reduced. The same applies to the rest.

  According to the injection apparatus of the liquid resin molding machine of the present invention, the mixing of the stock solution is made more uniform and the mixing ratio is stabilized. Therefore, the injection device of the liquid resin molding machine of the present invention greatly relaxes the restrictions on the combination of mixing due to the mixing ratio and viscosity difference of the mixed stock solution, and the possibility of molding by the liquid resin molding machine is greatly reduced. Make it more extensive. Therefore, the possibility of combining two liquids can be selected more freely than before, and this greatly advances the development of this type of stock solution.

It is an elevation view which shows the injection apparatus of the liquid resin molding machine of this invention in a cross section. It is the figure which looked at the injection apparatus of the liquid resin molding machine of this invention from upper direction, Comprising: It is a top view which shows the whole whole mixing apparatus especially. It is sectional drawing which expands and shows the principal part of the mixing apparatus of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Injection apparatus of liquid resin molding machine 10 Supply apparatus 20 Mixing apparatus 21 Mixing cylinder 21a Cylinder hole of mixing cylinder 21b Material supply hole 22 Mixing shaft 22b Convex protrusion 22c Double-row short pitch spiral groove 22e Cross spiral groove 40 Backflow prevention mechanism 39 communication member 39a communication hole 30 rotation drive device 50 plunger injection device 51 injection cylinder 51a cylinder hole of injection cylinder 52 plunger 55b end wall of cylinder hole 51

Claims (5)

A supply device for supplying at least two kinds of liquid resins at a predetermined ratio; a mixing device for mixing the supplied liquid resins; and the mixing device and the plunger injection for feeding the mixed liquid resin to a plunger injection device A liquid resin molding comprising: a communication member that communicates with the device; and a plunger injection device that, after the liquid mixture of the liquid resin is once measured by an injection cylinder by the retreat control of the plunger, the liquid mixture is injected by the advance control of the plunger In the injection device of the machine,
The mixing device communicates with the supply device via a material supply hole, and rotates or moves back and forth in the cylinder hole of the mixing cylinder, and innumerable convex protrusions are formed on most side surfaces thereof. A mixing shaft, a rotation drive device that controls the intensity of mixing by controlling rotation of the mixing shaft, and a backflow prevention mechanism that controls back and forth movement of the mixing shaft to prevent backflow of the mixed liquid. An injection apparatus for a liquid resin molding machine. ,
2. The liquid according to claim 1, wherein the convex protrusions of the mixing shaft are formed by a plurality of intersecting spiral grooves cut so as to cross each other along the mixing axis. Injection machine for resin molding machines.   The mixing shaft has the convex protrusions on the majority of the mixing shaft, and further has a double grooved short pitch spiral groove in the vicinity of the desired portion of the material supply hole, and the twist direction of the spiral groove is 2. The injection apparatus for a liquid resin molding machine according to claim 1, wherein the liquid resin is inclined in a direction in which the liquid resin is fed from the base side to the tip side when the mixing shaft rotates.   2. The liquid resin molding machine according to claim 1, wherein the communication hole of the communication member and the cylinder hole of the injection cylinder communicate with each other by opening the communication hole at a terminal surface of the cylinder hole of the injection cylinder. Injection device.   The adjustment of the mixing strength of the liquid resin in the injection device is performed by adjusting the rotational speed control of the mixing shaft and the retreat speed control of the plunger in a correlated manner. 5. A method for mixing an injection device for a liquid resin molding machine according to 4.

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