JP2010005853A - Scraper guide of plunger type injection machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a scraper guide in a plunger type injection machine which facilitates breakdown and falling of solidified matter mentioned below when a resin material leaked out from the rear end of injection cylinder of the injection machine is divided as fine thread-like solid matter to be discharged. <P>SOLUTION: This scraper guide installed at the rear end of the injection cylinder comprise a cylinder body part and a flange part and is configured such that a plurality of discharge grooves, formed on a guide hole through which a plunger shaft part of the flange part in inserted, may be inclined at a prescribed angle to the shaft center of the injection plunger. Preferably, the scraper guide is formed such that the prescribed angle is set such that the angle misalignment between the opening at the end face on the injection cylinder side and the opening at the end face on the remote side thereof of the discharge groove to surpass the angle made by adjacent discharge grooves. Also preferably, the scraper guide is formed such that the worked surface of the discharge groove is formed as an assemblage of linearly worked surfaces worked by a wire-cut electric discharge machine. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a scraper guide provided at the rear end of an injection cylinder of a plunger type injection device that injects molten resin in an injection cylinder with an injection plunger, and in particular, a resin material leaking from a guide hole of the injection plunger The present invention relates to a scraper guide having a discharge groove that divides and discharges into solidified products.

  An injection molding machine that injects molten resin in an injection cylinder with an injection plunger is typically a screw pre-plastic injection molding machine including a plunger type injection device. The plunger injection device 1 includes a plasticizing unit 2 and an injection unit 3 as shown in FIG. 5, and a plasticizing screw 21 is provided in a plasticizing cylinder 20 of the plasticizing unit 2, and an injection cylinder 30 of the injection unit 3. The injection plunger 31 is built in. The plasticizing cylinder 20 and the injection cylinder 30 communicate with each other at the junction 11. A hopper 24 for supplying a resin material is provided on the proximal end side of the plasticizing cylinder 20, and band heaters (not shown) are provided on the outer periphery of the plasticizing cylinder 20, the junction 11, and the injection cylinder 30.

  A check device 22 having a built-in hydraulic piston is connected to the rear end of the plasticizing cylinder 20, and a rotary drive device 23 such as a hydraulic motor is connected to the check device. The rear end of the plasticizing screw 21 is coupled to a hydraulic motor shaft (not shown) of the rotation drive device 23 via a hydraulic piston (not shown) in the check device 22. Therefore, the plasticizing screw 21 rotates in the plasticizing cylinder 20 to perform plasticization, and moves forward to prevent back flow of the resin material.

  The injection cylinder 30 is connected to a frame 41 of the injection driving device 40 by a connecting member 42, and a hydraulic cylinder 34 is provided in the frame 41. The injection plunger 31 is connected at its rear end to an injection piston 35 of an injection hydraulic cylinder 34 via a halved coupling 32 and a connecting rod 33. Therefore, the injection plunger 31 moves forward / backward in the injection cylinder 30 at each injection.

  In such an injection apparatus 1, the resin material supplied from the hopper 24 is plasticized by shearing heat generated by the rotation of the injection screw 21 and heating by a band heater, and is extruded by the rotation of the injection screw 21 and is injected by the injection cylinder 30. Weighed. At this time, the hydraulic piston of the check device 22 is maintained so as to be retractable, and the plasticizing screw 21 is retracted by the pressure of the molten resin to be sent to open the communication passage 11a. Next, the injection plunger 31 moves forward, and injection is performed in which the molten resin is filled from the nozzle 5 at the tip of the injection cylinder 30 into a mold cavity not shown. At this time, the hydraulic piston of the check device 22 advances the plasticizing screw 21 to prevent backflow that closes the communication path 11a.

  In the injection unit 3 described above, the plunger 31 is allowed to advance and retract between the plunger head 31a and the cylinder hole 30a so that the plunger head 31a (FIG. 6) does not bite into the cylinder hole 30a of the injection cylinder 30 during the injection operation. There is a slight gap to do. Further, the plunger head portion is formed short, and the diameter of the plunger shaft portion 31b excluding the head is formed slightly thinner than the diameter of the plunger head 31a. Therefore, every time the injection plunger 31 advances in the injection cylinder 30, the molten resin gets over the plunger head 31a and enters the gap between the plunger shaft portion 31b and the cylinder hole 30a behind it. The leaked resin gradually moves to the rear end side and fills the gap between the plunger shaft portion 31b and the inner hole 51d of the discharge guide 51 (corresponding to the scraper guide of the present invention), and finally the discharge guide. Leak from the rear end of 51. There are various ways of leakage depending on the resin material or the resin temperature. Therefore, the applicant of the present application has proposed three proposals for the discharge device in which the discharge guide 51 can be exchanged in accordance with various leak modes, and has dealt with any of these modes.

  Among them, Patent Document 1 (Patent Registration No. 3234869) proposed a discharge guide for dividing a leaked resin into fine solidified solids and discharging them. The discharge guide is shown as 51 in FIG. 3 of Patent Document 1 corresponding to FIG. 6, and is attached so that its front end comes into contact with the rear end of the injection cylinder 30, and its cylindrical portion 51b. The temperature of the outer periphery is appropriately adjusted by the temperature adjusting means 53. A large number of discharge grooves 51f are formed adjacent to each other at equal intervals along the axial direction of the injection plunger 31 in the guide hole 51e at the rear portion of the discharge guide 51 fitted to the plunger shaft portion 31b.

  By such a discharge guide 51, the temperature of the resin material is appropriately adjusted until the resin material is discharged outside from the discharge groove 51f, and thereafter, the resin material is discharged as a large number of thin solidified products. In many cases, this thin solidified product becomes brittle due to the heat history until it leaks out, so that it is easily broken by its own weight or as the injection plunger 31 moves forward and backward. Further, even when the solidified product is difficult to break, it collides with the coupling 32 and finally breaks in most cases.

  On the other hand, in the vertical injection device, the discharged thin solidified product often lies down in the lateral direction, and therefore breakage due to collision with the coupling as described above is unlikely to occur. In this case, the solidified material grows long and hangs around the injection device, which is not preferable. Therefore, the applicant of the present application has proposed a discharge device for a vertical molding machine in Patent Document 2 (Japanese Patent No. 3558562). In addition to the discharge guide having the discharge groove for thinning, this device includes a cutter that moves along the injection plunger (up and down in the vertical shape), and presses the cutter against the discharge guide periodically to solidify the product. Disconnect. The apparatus includes a suction device that sucks and discharges the cut thin wire. Regarding this latter device, Patent Document 3 (Japanese Patent Laid-Open No. 2000-190365) proposes a device for solving the same problem. The document also introduces various aspects of the leakage dividing mechanism, but differs from Patent Document 2 in that the material leaked outside in an undivided state is divided immediately after the leakage.

Patent Registration No. 3234869 Patent Registration No. 3558562 JP 2000-190365 A

  However, the applicant of the present application considers that there is still room for improvement in the device disclosed in the above patent document. This is the case when the thin-line solidified product does not break when the resin material does not become brittle. In that case, for example, in the apparatus of Patent Document 1, the solidified product is discharged from the discharge groove while being stuck to the injection plunger. And the solidified material grows along the injection plunger and hardly breaks in many cases. Further, the thin solidified product itself is firmly bonded and is not easily broken. In this case, even the apparatus of Patent Document 2 is generated in the same manner, and suction becomes impossible. Moreover, in the apparatus of patent document 3, anxiety remains in dividing after leakage.

  Accordingly, an object of the present invention is to provide a scraper guide for an injection apparatus in which a solidified product that has been divided and discharged from a discharge groove of a scraper guide is easily broken after coming out of the discharge groove.

  In order to achieve the above object, the scraper guide of the plunger type injection device according to the first embodiment of the present invention is provided at the rear end of the injection cylinder of the plunger type injection device that injects the plasticized resin material by the injection plunger. In the scraper guide that divides the resin material leaked from the injection cylinder into a plurality of thin solidified products and discharges the resin material, a plurality of discharge grooves formed in guide holes that guide the injection plunger on the rear end side Are inclined at a predetermined angle with respect to the injection plunger axis.

  The scraper guide according to the first embodiment includes, as a second embodiment, a cylindrical portion on the injection cylinder side and having an inner hole substantially equal to the cylinder hole of the injection cylinder, and a distance from the injection cylinder. A flange portion having the guide hole on the other side, and the predetermined angle of the discharge groove is such that the discharge groove formed in the guide hole has an opening on the injection cylinder side and a side away from the opening. The angle formed between the openings may be an angle formed approximately equal to the angle formed by the adjacent discharge grooves.

  Moreover, the processed surface of the said discharge groove | channel of said 2nd embodiment may be formed as a collection of the linear processing surface processed with the wire cut electric discharge machine as a 3rd embodiment.

  According to the first embodiment of the present invention, the scraper guide provided at the rear end of the injection cylinder of the plunger type injection device has a plurality of discharge grooves in the guide hole for guiding the injection plunger on the rear end side. The discharge groove is formed so as to incline at a predetermined angle with respect to the injection plunger shaft center, so that the thin solidified material discharged from the discharge groove of the scraper guide is re-appeared by the advance / retreat operation of the injection plunger. Of course, it is not pulled back into the discharge groove, but is discharged not in the direction of the injection plunger but in a direction inclined with respect to the injection plunger, that is, in a direction away from the injection plunger. Therefore, the thin solidified product discharged from the scraper guide according to the present invention spreads outward without adhering around the injection plunger and easily breaks. Also, since the molten resin material just before entering the discharge groove moves somewhat with the injection plunger and repeats tearing and recombination, it solidifies eventually and is finally solidified solidly discharged outside from the discharge groove Things become more prone to tearing due to their reduced degree of bonding. Due to the above synergistic action, the solidified product divided and discharged in a thin line shape breaks one after another without falling long and falls naturally.

  Moreover, according to the scraper guide according to the second embodiment of the plunger type injection device of the present invention, the scraper guide has a cylindrical portion on the injection cylinder side and a flange portion having the guide hole on the side away from the cylindrical portion. The predetermined angle of the discharge groove of the guide hole is an angular deviation between the discharge groove opening on the injection cylinder side and the discharge groove opening on the remote side. Since the angle formed is almost equal to the angle formed, there is no room for the resin passing through the discharge groove to move in parallel along the injection plunger axis direction, and as a result, there is no phenomenon that the resin stays stuck on the injection plunger side. do not do. Therefore, there is no occurrence of leakage resin remaining on the outer periphery of the injection plunger, which is scraped off by the scraper guide.

  Further, according to the scraper guide according to the third embodiment of the plunger type injection device of the present invention, the processed surface of the discharge groove is formed as a set of linear processed surfaces processed by a wire cut electric discharge machine. In this case, the processing of processing the discharge groove inclined from the center axis of the guide hole can be easily realized in combination with the small thickness of the flange portion. Further, since the processed discharge groove is inclined, the processing depth becomes shallower in the middle than the both end surfaces, and is narrowed in the middle. Therefore, the resin in the discharge groove does not move with the advance / retreat operation of the injection plunger, and as a result, the effects of the first embodiment and the second embodiment are more remarkably exhibited.

  Hereinafter, the scraper guide 61 provided at the rear end of the injection cylinder 30 of the plunger type injection device (hereinafter simply referred to as the injection device 1) of the present invention will be described. The overall configuration of the injection device 1 is shown in FIG. This is roughly the same as that described in FIG. 6 (FIGS. 1, 2, and 3). Therefore, those same members are denoted by the same reference numerals, and the description thereof is simplified. 2 is a cross-sectional view taken along line BB in FIG. 3, and FIG. 3 is a cross-sectional view taken along line AA in FIG.

  Here, the injection cylinder 30 to which the scraper guide 61 of the present invention is attached will be supplementarily described. The injection cylinder 30 is fixed to the connecting member 42 through the small diameter cylindrical portion 30b and through the heat insulating member 43. Therefore, the heat transmitted from the rear end of the injection cylinder 30 to the scraper guide 61 is suppressed as much as possible. On the other hand, for the injection plunger 31 (hereinafter simply referred to as a plunger), the diameter of the plunger shaft portion 31b excluding the plunger head 31a is formed to be smaller than the diameter of the plunger head 31a, and the boundary between the plunger head 31a and the plunger shaft portion 31b. As a result, a slight step portion is formed, and a slight gap is formed between the cylinder hole 30a of the injection cylinder 30 and the plunger shaft portion 31b. Therefore, the molten resin leaking from the gap between the plunger head 31a and the cylinder hole 30a during the injection operation fills the gap between the plunger shaft portion 31b and the cylinder hole 30a, and is pushed out backward by the step portion every time it is weighed. Finally, it is pushed out from the rear end of the injection cylinder 30.

  As described above, a scraper guide as described below is provided at the rear end of the injection cylinder 30 in order to divide and discharge the leaked resin extruded from the rear end of the injection cylinder 30 into thin solidified products.

  In the present invention, the scraper guide 61 is configured as a combination member including a cylindrical body portion 61b on the injection cylinder 30 side and a flange portion 61c on the side away from the cylinder. And the front end 61a of the cylindrical part 61b is fitted into the hole at the rear end of the injection cylinder 30, and the flange portion 61c is fastened to the back surface of the front end of the connecting member 42 with a bolt. Of course, the scraper guide 61 is concentrically fixed to the rear end of the injection cylinder 30. A dropping port 42b is opened on the lower surface of the connecting member 42 located below the flange portion 61c so that the resin discharged from the rear end of the scraper guide 61 falls outside the apparatus.

  An inner hole 61 d is formed in the cylindrical portion 61 b of the scraper guide 61, and the inner diameter of the inner hole 61 d is formed to be approximately the same as the inner diameter of the cylinder hole 30 a of the injection cylinder 30. The flange portion 61c is formed with a guide hole 61e having an inner diameter almost the same as the outer diameter of the plunger shaft portion 31b. The discharge hole divides the leaked resin into fine solidified solid matter into the guide hole 61e. 61f are formed at equal intervals.

  Regarding the temperature control of the scraper guide 61, the cylindrical portion 61b of the scraper guide 61 is configured as a compact member in contact with the rear end of the injection cylinder 30 with as small an area as possible, so that heat transmitted to the guide 61 is minimized. Therefore, the temperature is not easily affected by the temperature of the injection cylinder 30. In addition, since the outer periphery of the cylindrical portion 61b is controlled to be cooled by the cooling pipe 53, the leakage resin moving through the inner hole 61d is cooled to near the solidification temperature so as to be solidified at the flange portion 61c, and is in a semi-molten state. become.

  The scraper guide 61 described above is characterized by the discharge groove 61f formed in the flange portion 61c. That is, the discharge groove 61 f is formed in the guide hole 61 e of the flange portion 61 c as a groove inclined at a predetermined angle with respect to the axis of the plunger 31. One of the embodiments is a groove in which the discharge groove 61f is processed as a set of straight processed surfaces, and is, for example, electric discharge processed by the wire electrode W as shown in FIG. In the figure, the figure (c) and its enlarged view (e) show that the wire electrode W positioned perpendicularly (perpendicularly) to the paper surface is on the flange portion 61c of the scraper guide inclined at a predetermined angle with respect to the paper surface (horizontal plane). A state of contact is shown. The predetermined angle is represented as an angle θ formed by the center line C of the flange portion 61c and the wire electrode W in FIG. Incidentally, FIG. (B) is a BB arrow view of FIG. (A), it is a front view of the guide partly shown in cross section, and FIG. (D) and FIG. It is an enlarged view of D section of E, and E section of FIG. In addition, in order to easily understand the drawing, only one discharge groove is displayed in the drawings excluding the drawings (b) and (d).

  Such a discharge groove 61f has, for example, a radius of 2.2 mm around the guide hole 61e when the outer diameter (nominal diameter) of the plunger 31 is 32 mm and the thickness dimension of the guide hole 61e is about 10 mm. 18 semicircular grooves are formed at equal intervals. When the plunger diameter is increased, the number of discharge grooves 61f is increased without changing the cross-sectional area of each groove.

  In particular, the predetermined angle θ of the discharge groove 61f with respect to the plunger axis C is opened at the discharge groove 61ff opened at the end face on the injection cylinder side and at the end face away from the injection cylinder, as shown in FIG. The phase shift of the discharge groove 61fr is inclined so as to be twisted by an angle exceeding the pitch of the adjacent groove. This form is the same even when the discharge groove is a straight line or a form processed as a helical chord winding which will be described later as another embodiment.

  In particular, the wire-cut electric discharge machining for machining the discharge groove 61f into a linear inclined groove is, for example, as follows. That is, although not shown in the drawings, this is a process in which a rotary table having an inclined work mounting surface is installed on a processing table of a wire electric discharge machine, and the flange portion 61c attached to the rotary table is wire cut. Then, the rotary table rotation indexing control (C-axis control) and the machining table contour machining control (XY control) are synchronized, and machining similar to internal gear cutting is performed. Here, the inclination angle of the rotary table with respect to the horizontal plane is θ in FIG. 4A, and the wire electrode W in the vertical posture and the center line C of the flange portion 61c in the inclined posture intersect at an angle θ. The reference position for the contour control of the XY table is CC in FIG. Then, during contour processing, the wire electrode W comes into contact with the discharge groove 61f as shown in FIG.

  When the processed surface is made linear in this way, the depth of the processed discharge groove 61f becomes shallow in the middle of the scraper guide 61c, and is narrowed in the thickness direction. This is because the processing depth of the discharge groove 61f with respect to the cylindrical surface of the guide hole 61e is different between the center position and the both end positions as shown in FIGS. In other words, the degree of the restriction depends on the thickness dimension, the radial dimension, and the inclination angle of the flange portion 61c. Actually, in this figure, the distance of the wire electrode w viewed from the central axis C of the flange portion 61c is farther from the central side by about ½ pitch from the central axis C on both end surfaces.

  As described above, in the present invention, since the discharge groove 61f is inclined with respect to the center line C of the flange, the leakage resin pushed out to the rear end side in the discharge groove 61f at each injection is the plunger shaft. The phenomenon of moving while sticking to the side does not occur at all. Therefore, the fine-line resin material once discharged out of the discharge groove 61f is not pulled back into the discharge groove 61f. Further, since the thin solidified product discharged from the scraper guide 61 is discharged in a direction inclined with respect to the plunger 31, that is, in a direction away from the plunger, the solidified product adheres around the plunger 31. It spreads to the outside and becomes easier to break. Further, since the semi-molten leakage resin immediately before entering the discharge groove 61f moves somewhat together with the plunger 31 and repeats tearing and recombination, it is finally solidified and thinly solidified and discharged to the outside from the discharge groove 61f. The degree of bonding of the objects is reduced, and the thin solidified product itself is more easily broken. Due to the above synergistic action, the leaked thin linear solidified product becomes more easily ruptured and more easily falls. In addition, when the discharge grooves 61f are subjected to electric discharge machining by the wire electrode W, the phenomenon that the leakage resin moves together with the plunger shaft 31b while being stuck to the plunger shaft 31b side is caused by narrowing the discharge grooves in the middle. No longer occur.

  Moreover, in the present invention, since the discharge groove 61f is inclined at a predetermined angle as described above, there is no room for the resin passing through the discharge groove to move linearly along the plunger axis direction, and the plunger side The phenomenon of moving while sticking is reliably suppressed. Therefore, there is no occurrence of leakage resin remaining scraped off from the outer periphery of the injection plunger 31 by the scraper guide 61. Further, as described above, the scraper guide 61 is configured as a divided product of the cylindrical portion 61b and the thin flange portion 61c on the rear end side, and the inclined discharge groove 61f is processed by wire electric discharge machining only for the thin flange portion 61c. In this case, there is an effect that the processing of the discharge groove 61f itself becomes easy.

  On the other hand, as another embodiment, the discharge groove 61f may be processed as a helical string winding. The discharge groove can be machined by moving a cutting blade to be grooved by the guide inner hole 61e in the axial direction (Z-axis control) and appropriately controlling the rotation of the guide (C-axis control). More specifically, this processing may be performed by a die-sinking electric discharge machine that processes a string winding with a tip (not shown) of a processing electrode formed in the cross-sectional shape of the discharge groove 61f. This electric discharge machining is possible because the inner hole has a relatively small diameter. In addition, since the flange portion 61c is thin, it is convenient for electric discharge machining that takes time for machining.

  In this embodiment, the cross-sectional shape of the discharge groove 61f is the same from the injection cylinder side to the opposite side, and is slightly different from the discharge groove shape by the wire cut electric discharge machining in terms of the groove depth. However, since it is the same that it is inclined with respect to the plunger axis, the basic operation and effects are the same as described above.

It is sectional drawing which shows the outline of the screw preplar type injection device with which the injection cylinder containing the scraper guide of this invention was integrated. It is sectional drawing which expands and shows the structure around the scraper guide of FIG. 1, Comprising: It is the BB arrow line view of FIG. It is the figure which looked at the structure around the scraper guide of this invention from the back, Comprising: It is AA arrow sectional drawing of FIG. It is a figure explaining one Embodiment of the discharge groove | channel of the scraper guide of this invention, Comprising: It is the figure which looked at the state contact | abutted with a wire electrode from the three directions when carrying out electric discharge machining. Among these, FIG. (A) is the figure which looked at the state in process from the side, Comprising: It is AA arrow sectional drawing cut | disconnected along the center of the scraper guide of FIG. (C), FIG. (B) Fig. 6 (a) is a front view of the guide taken along the line B-B in Fig. (A). Fig. (C) shows that the wire electrode positioned perpendicularly to the scraper guide inclined at a predetermined angle is in contact with the guide. Figures (d) and (e) are detailed views of part D in figure (b) and part E in figure (c), respectively. It is sectional drawing which shows the outline of the screw preplar type injection device with which the injection cylinder containing the conventional scraper guide was integrated. FIG. 6 is an enlarged cross-sectional view illustrating a configuration around a scraper guide in FIG. 5.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Plunger type injection device 3 Injection unit 30 Injection cylinder 30a Cylinder hole 31 of injection cylinder Injection plunger 61 Scraper guide 61b Scraper guide cylindrical part 61c Scraper guide flange part 61d Scraper guide cylindrical part inner hole 61e Scraper guide Guide hole 61f Scraper guide discharge groove C Injection plunger axis (center axis of scraper guide)
θ Predetermined angle

Claims (3)

  A scraper that is provided at the rear end of an injection cylinder of a plunger type injection device that injects a plasticized resin material with an injection plunger, and that divides the resin material leaking from the injection cylinder into a plurality of fine-line solidified products and discharges them. In the guide, a plurality of discharge grooves formed in a guide hole for guiding the injection plunger on the rear end side thereof are formed so as to be inclined at a predetermined angle with respect to the injection plunger axis, respectively. Scraper guide for plunger injection device.   The scraper guide comprises a cylindrical portion having an inner hole substantially equal to the cylinder hole of the injection cylinder on the injection cylinder side, and a flange portion having the guide hole on a side away from the injection cylinder. The predetermined angle of the discharge groove forms an angular deviation between the opening on the injection cylinder side of the discharge groove formed in the guide hole and the opening on the side away from the discharge groove. 2. A scraper guide for a plunger type injection device according to claim 1, wherein the angle is an angle formed substantially equal to the angle.   The scraper guide of the plunger type injection device according to claim 2, wherein the processed surface of the discharge groove is formed as a set of linear processed surfaces processed by a wire cut electric discharge machine.

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