JP4522943B2 - Pre-plastic injection device - Google Patents

Description

  The present invention relates to an injection apparatus of an injection molding machine, and more particularly to a pre-plastic injection apparatus that injects a molten resin supplied from a plasticizing apparatus by a plunger.

  The injection apparatus of the injection molding machine is roughly classified into an in-line type injection apparatus and a pre-plastic (pre-plasticizer) type injection apparatus. In the in-line type injection device, the molten resin is accumulated on the front side of the screw while rotating the screw to melt the resin, and the molten resin is injected to advance the screw. In the pre-plastic injection device, a plasticizing device that melts the resin and an injection device that injects the molten resin are provided independently, and the resin melted by the plasticizing device is supplied to the injection chamber of the injection device and injected. The molten resin is injected by advancing the plunger provided in the chamber. Compared to the in-line type injection device, the pre-plastic type injection device has an advantage that the resin can be plasticized and injected stably.

  In the pre-plastic injection device, the resin melted by the plasticizing device is filled in an injection chamber connected to the injection nozzle of the injection device, and the molten resin once stored in the injection chamber is injected from the injection nozzle by pressing with a plunger. The injection chamber is a space formed on the front side of the plunger provided to be movable back and forth in the plunger cylinder, and a molten resin supply passage extending from a molten resin discharge nozzle of the plasticizing apparatus is connected to the injection chamber.

In an example of a conventional pre-plastic injection device, the plasticizing cylinder of the plasticizing device is arranged in a V shape with the nozzle side at the top of the plunger cylinder of the injection device, and the molten resin discharge nozzle of the plasticizing device is injected. A molten resin supply passage for connecting to the injection chamber of the apparatus is provided (for example, see Patent Document 1).
JP 2000-263600 A

  As described above, in the pre-plastic injection device, since the molten resin is pressed and injected by the plunger, the plunger is configured to be able to reciprocate within the plunger cylinder. That is, since the plunger is slidable with respect to the plunger cylinder, a certain amount of clearance is provided between the plunger and the plunger cylinder.

  When the molten resin is brought to a high pressure on the front side of the plunger, the molten resin enters the clearance slightly but protrudes in the direction opposite to the injection chamber along the plunger. The overflowing molten resin accumulates in the clearance every time it is injected by the plunger and gradually moves in the direction opposite to the injection chamber.

  The plunger cylinder is heated to maintain the resin in a molten state, and the resin accumulated in the clearance may be carbonized by heat and stick to the plunger. If the resin sticks to the plunger, the sliding resistance of the plunger increases, which causes a problem that the plunger cannot be moved.

  In addition, in order to remove the resin stuck to the plunger, the plunger must be extracted from the plunger cylinder, which causes a problem that maintenance work becomes large.

  The present invention has been made in view of the above-described problems, and provides a pre-plastic injection device that can easily discharge resin that has entered between a plunger and a plunger cylinder when performing an injection operation. For the purpose.

In order to achieve the above-described object, according to the present invention, there is provided a pre-plastic injection device having a resin injection device for injecting a molten resin supplied from a resin plasticizing device, wherein the resin injection device is disposed in a plunger cylinder. A plunger configured to be rotatable in the cylinder, a resin discharge hole formed in the plunger cylinder, in which a part of the outer peripheral surface of the plunger is exposed, and a scraper provided in the resin discharge hole and extending in the axial direction of the plunger. possess a member out, and an elastic body for urging the scraping member to the plunger, scrape-out member, preplasticization type injection apparatus characterized by contained in the resin removing mechanism attached to the plunger cylinder is provided The

Above preplasticization injection apparatus, the take-out member, an inclined state with respect to the outer peripheral surface of the plunger, and serial being shifted from the center of the resin discharge hole, the may be arranged in at least one state. Moreover, the edge part which contact | abuts the plunger of a scraping member is good also as being convex shape or an inclined shape.

  In addition, the pre-plastic injection device according to the present invention preferably has means for moving the plunger in the axial direction while rotating the plunger. Moreover, it is preferable that the plunger has a small diameter part having an outer diameter smaller than the outer diameter of the tip part, and the scraping member abuts on the outer peripheral surface of the small diameter part. Furthermore, it is preferable that the small diameter part of the plunger is connected to the tip part of the plunger with a step, and the scraping member abuts on the outer peripheral surface of the small diameter part in the vicinity of the step. Or the taper part is provided between the small diameter part of the plunger, and the front-end | tip part of a plunger, and a scraping member is good also as contacting the outer peripheral surface of a taper part.

  According to the above-mentioned present invention, the molten resin that has entered between the plunger and the plunger cylinder can be scraped off from the plunger by the scraping member when the plunger rotates, and the molten resin adhering to the plunger is cured. It is possible to prevent the movement of the plunger from being hindered by carbonization or carbonization.

  First, an example of a pre-plastic injection device to which the present invention is applied will be described with reference to FIGS. FIG. 1 is a cross-sectional view showing a plasticizing device of a pre-plastic injection device to which the present invention is applied, and FIG. 2 is a cross-sectional view showing an injection device of the pre-plastic injection device to which the present invention is applied. The plasticizer 10 shown in FIG. 1 and the resin injection device 30 shown in FIG. 2 constitute a pre-plastic injection device to which the present invention is applied.

  A plasticizing apparatus 10 shown in FIG. 1 is an apparatus for melting resin pellets as a resin raw material and supplying them to an injection apparatus 30. The plasticizing apparatus 10 includes a plasticizing cylinder 12, a screw 14 provided in the plasticizing cylinder 12, a measuring motor 16 that rotationally drives the screw 14, and an encoder 18 that detects the amount of rotation of the measuring motor 16. Have

  A hopper port 20 is provided on the metering motor 16 side of the plasticizing cylinder 12 in order to supply resin raw materials such as resin pellets to the screw 14 in the plasticizing cylinder 12. A cylinder heating heater 22 is wound around the plasticizing cylinder 12.

  When the screw 14 is rotated by the metering motor 16, the resin pellet supplied from the hopper port 20 is fed forward (right side in the figure) by the screw 14. At this time, the resin pellets are compressed between the screw 14 and the inner wall of the plasticizing cylinder 12 and are melted by the shear heat and heat supplied from the cylinder heating heater 22. Then, the molten resin is fed into the tip of the screw 14.

  The tip of the screw 14 is configured to protrude into a screw nozzle chamber 32b formed in a plunger cylinder 32 of the injection device 30 described later, and the molten resin is a groove formed in the plunger 34 from the plunger cylinder 32. It is supplied to the injection chamber 38 via 34a.

  The rotation amount of the metering motor 16 is controlled based on the output signal of the encoder 18, and the rotation amount of the screw 12 is controlled. As a result, an appropriate amount of molten resin is supplied to the injection device 30.

  A resin injection device 30 shown in FIG. 2 includes a plunger cylinder 32, a plunger 34 that is axially movable and rotatable within the plunger cylinder 32, and a nozzle portion 36 provided at the front end of the plunger cylinder 32. The plunger drive unit 60 drives and rotates the plunger 34 in the axial direction.

  A nozzle portion 36 is provided at the tip of the plunger cylinder 32, and an injection chamber 38 is formed on the front end side of the plunger 34 inside the nozzle portion 36. The injection chamber 38 is connected to the nozzle 36a, and when the plunger 34 moves forward, molten resin is injected from the nozzle 36a.

  A plunger cylinder heating heater 40 is wound around the plunger cylinder 32, and a nozzle heating heater 42 is also wound around the nozzle portion 36. The plunger cylinder heating heater 40 and the nozzle heating heater 42 heat the plunger cylinder 32 and the nozzle portion 36 to a temperature equal to or higher than the melting temperature of the resin in order to maintain the molten resin supplied from the injection device 10 in a molten state. .

  The distal end surface of the plasticizing cylinder 12 of the resin plasticizing apparatus 10 is fixed to the plane formed on the outer periphery of the plunger cylinder 32 of the resin injecting apparatus 30, so that the plasticizing apparatus 10 and the injection apparatus 30 are Together, a pre-plastic injection device is configured. In a state where the plasticizing cylinder 12 of the injection device 10 is fixed to the plane formed on the outer periphery of the plunger cylinder 32, the tip portion of the screw 14 in the plasticizing cylinder 12 is the plane portion 32 a of the plunger cylinder 32. It protrudes into the space formed toward the plunger 34. This space is referred to as a screw nozzle chamber 32b.

  The plunger cylinder 32 is attached to a fixed portion 44, and the fixed portion 44 is fixed to the front flange 46. Therefore, the plunger cylinder 32, the fixing portion 44, and the front flange 46 are integrated. A rear flange 50 is attached to the front flange 46 via a plurality of guide rods 48. That is, one end of the guide rod 48 is fixed to the front flange 46 by the bolt b1, and the other end is fixed to the rear flange 50 by the bolt b2.

  Here, a plunger driving unit 60 is provided above the front flange 46. The plunger drive unit 60 is a drive mechanism for moving and rotating the plunger 34 in the axial direction within the plunger cylinder 32.

  First, the mechanism which moves the plunger 34 to the axial direction among the plunger drive parts 60 is demonstrated.

  The movement of the plunger 34 in the axial direction is an operation for injecting the molten resin supplied to the injection chamber 38 in the nozzle portion 36 from the nozzle 36a.

  A movable plate 62 is provided between the front flange 46 and the rear flange 50 and is movable between the front flange 46 and the rear flange 50 by being guided by the guide rod 48. That is, the movable plate 62 is slidably supported by the guide rod 48 via the bush 64.

  An injection motor 66 is fixed to the outer peripheral portion of the movable plate 62. Further, a bearing holder 68 is rotatably supported at the center portion of the movable plate 62 via radial bearings br1 and br2. A belt 74 is stretched between a small pulley 70 fixed to the shaft of the injection motor 66 and a large pulley 72 fixed to the bearing holder 68 with a bolt b3. Thus, when the injection motor 66 is driven, the rotation is transmitted to the bearing holder 68 via the pulleys 70 and 72 and the belt 74, and the bearing holder 68 rotates. The bearing br1 is fixed to the movable plate 62 via the pressing plate 63 by a bolt b8.

  A ball screw shaft 76 extending toward the rear flange 50 on the center axis thereof is fixed to the bearing holder 68 by a bolt b4. The ball screw shaft 76 is engaged with the ball screw nut 80 to constitute a motion direction conversion mechanism. A load cell 78 as a pressure detection unit for detecting the resin pressure applied to the plunger 34 is attached to the rear part of the ball screw nut 80 by a bolt b5. The load cell 78 is fixed to the rear flange 50 by a bolt b6 together with the load cell retainer. Here, the load cell retainer 79 is an annular member, and is provided to make the tightening force applied to the load cell 78 uniform when the bolt b6 is tightened.

  Accordingly, when the bearing holder 68 rotates and the ball screw shaft 76 rotates, the bearing holder 68 moves in the axial direction by the action of the ball screw constituted by the ball screw shaft 76 and the ball screw nut 80. At this time, since the movable plate 62 is rotatable with respect to the bearing holder 68 but is fixed in the axial direction, the movable plate 62 also moves in the axial direction together with the bearing holder 68 and is fixed to the movable plate 62. The injection motor 66 is also moved with the movable plate 62.

  A rotating shaft 82 is rotatably supported inside the bearing holder 68 via a thrust bearing br3. The thrust bearing br3 is pressurized by a tightening nut 81. Therefore, the rotating shaft 82 can move only in the axial direction together with the bearing holder 68 without rotating together with the bearing holder 68. The rotating shaft 82 has a spline hole in which a spline is formed on the inner periphery.

  A spline end portion 34 b of the plunger 34 extending from the plunger cylinder 32 is engaged with the spline hole. A plunger connecting portion 84 is fixed near the spline end portion 34 b of the plunger 34, and the plunger connecting portion 84 is attached to the rotating shaft 82. Therefore, the plunger 34 can move in the axial direction along with the axial movement of the rotation shaft. That is, the plunger 34 can be reciprocated in the axial direction by rotating the injection motor 66 forward and backward. As the plunger 34 reciprocates, the molten resin is injected.

  The injection motor 66 is provided with an encoder 66a for detecting the rotation amount of the shaft. The rotation amount of the injection motor 66 is controlled based on the detection signal from the encoder 66a, and thereby the movement amount of the plunger 34 is controlled.

  Next, a rotation mechanism that rotates the plunger 34 in the plunger drive unit 60 will be described.

  When the molten resin is supplied from the resin plasticizing apparatus 10 to the injection chamber 38, the plunger 34 has the groove 34a aligned with the resin inflow hole 32c, and the molten resin fed into the screw nozzle chamber 32b by the screw 14 is injected into the injection chamber. 38. However, when the molten resin supplied to the injection chamber 38 is injected from the nozzle 36a, the molten resin does not shut off the passage of the molten resin between the groove 34a and the screw nozzle chamber 32b. 10 side).

  Therefore, in the above-described pre-plastic injection device, at the time when the molten resin has been supplied to the injection chamber 38, or just before that, the plunger 34 is rotated, for example, 180 degrees so that the groove 34a is detached from the resin inflow hole 32c. To. Thereby, the resin inflow hole 32c is closed by the outer peripheral surface of the plunger 34, and the passage of the molten resin between the screw nozzle chamber 32b and the injection chamber 38 is blocked.

  A rotation mechanism is provided to rotate the plunger 34 described above. As described above, the plunger 34 is attached to the rotating shaft 82 by the plunger connecting portion 84 and can rotate integrally with the rotating shaft 82. A large pulley 86 is fixed to the rotating shaft 82 by bolts b <b> 7, and the rotating shaft 82 can rotate together with the large pulley 86.

  Here, a seal opening / closing motor 88 is fixed to the outer peripheral portion of the movable plate 62, and a small pulley 90 is attached to the shaft of the sealing opening / closing motor 88. A belt 92 is stretched between the small pulley 90 and the large pulley 86 of the rotating shaft 82. Accordingly, when the seal opening / closing motor 88 is driven and the small pulley 90 rotates, the rotation is transmitted to the rotating shaft 82 via the belt 92 and the large pulley 86, and the rotating shaft 82 rotates. As a result, the plunger 34 fixed to the rotating shaft 82 rotates, the groove 34 a is detached from the resin inflow hole 32 c, and the resin inflow hole 32 c is closed by the outer peripheral surface of the plunger 34.

  The seal opening / closing motor 88 is provided with an encoder 88a for detecting the rotation amount of the shaft. The drive of the seal opening / closing motor 88 may be controlled based on a detection signal from the encoder 88a. However, in this embodiment, as described later, the operation of the seal opening / closing motor 88 is controlled and stopped by detecting the rotational position of the portion that rotates together with the plunger 34.

  The pre-plastic injection device to which the present invention is applied has the above-described configuration, and the configuration relating to the supply of molten resin from the resin plasticizing device 10 to the resin injection device 30 is simplified. That is, the tip of the screw 14 of the plasticizing device 10 protrudes into a screw nozzle chamber 32b formed inside the plunger cylinder 32, and a nozzle that normally discharges the molten resin provided in the plasticizing device 10 is This corresponds to a resin inflow hole 32 c formed in the plunger cylinder 32. Therefore, the nozzle (resin inflow hole 32 c) of the plasticizing apparatus 10 is directly connected to the groove 34 a of the plunger 34.

  The groove 34 a of the plunger 34 extends to the front end surface of the plunger 34 and connects the resin inflow hole 32 c and the injection chamber 38. Therefore, the groove 34 a of the plunger 34 functions as a molten resin supply passage for supplying the molten resin from the resin plasticizing apparatus 10 to the injection chamber 38.

  When the supply of the molten resin to the injection chamber 38 is completed, the groove 34a is brought into a position not connected to the resin inflow hole 32c by driving the seal opening / closing motor 88 and rotating the plunger 34 as described above. Thereby, the connection between the injection chamber 38 and the screw nozzle chamber 32b is cut off. Therefore, by advancing the plunger 34, the molten resin in the injection chamber 38 can be injected from the nozzle 36a without flowing back to the screw nozzle chamber 32b. That is, the rotation of the plunger 34 provides a function of a check valve or a stop valve that has been conventionally provided.

  Here, a clearance (a slight gap) is provided between the plunger 34 and the plunger cylinder 32 so that the plunger 34 can move within the plunger cylinder 32. When the molten resin is supplied to the injection chamber 38 and then the plunger 34 is advanced to inject the molten resin under pressure, the molten resin enters the clearance. Each time the injection operation is repeated, the molten resin enters the clearance slightly but moves along the plunger 34 to the opposite side of the injection chamber 34.

  As shown in the enlarged view of FIG. 3, the plunger 34 has a thick portion where the groove 34a is formed on the injection chamber 38 side, and a small diameter portion 34c which is a central portion extending from the portion 34a is slightly narrowed. . This is because if the clearance with the plunger cylinder 32 is reduced over the entire plunger 34, the sliding resistance is increased. Therefore, the clearance is reduced only on the injection chamber 38 side, and the leakage resistance is reduced while reducing the sliding resistance. It is to do.

  Therefore, a step is formed in the plunger 34 as shown by an arrow A in FIG. Here, when the molten resin enters the clearance from the injection chamber 38 side and gradually moves to the small diameter portion 34c of the plunger 34, the resin stays at the corner of the step, and the retained resin is burnt (carbonized). ) Is likely to occur.

  Therefore, as shown in FIG. 4, by providing a tapered portion 34d so as to be gently connected to the small diameter portion 34c without a step, the resin in the clearance moves smoothly along the plunger 34 and reaches the small diameter portion 34c. Residue of the resin until it is done can be eliminated.

  However, even if the stagnation of the resin is eliminated, it does not prevent the resin from entering the clearance, and the resin still enters the clearance between the plunger 34 and the plunger cylinder 32 and moves to the back. .

  Therefore, the pre-plastic injection device according to the present invention is provided with a resin removal mechanism 100 (see FIG. 2) for removing the resin that has moved to the small diameter portion 34c or the tapered portion 34d of the plunger 34 to the outside of the plunger cylinder 32. Yes.

  As shown in FIG. 2, the resin removing mechanism 100 includes an outer cylinder portion 102, an inner cylinder portion 104 provided inside the outer cylinder portion, and a scraping plate 106 attached to the inner cylinder portion 104. The outer cylinder portion 102 is fixed to a resin discharge hole formed in the plunger cylinder 32. The resin discharge hole is formed to be perpendicular to the plunger hole (cylinder) in which the plunger 34 is accommodated and to extend to the plunger hole. Therefore, a part of the outer peripheral surface of the plunger 34 is exposed inside the resin discharge hole.

  The position of the resin discharge hole is desirably such that the outer peripheral surface of the plunger 34 exposed inside is a portion close to a step in the small diameter portion 34 c of the plunger 34 or a tapered portion 34.

  The inner cylinder part 104 extends deeper than the outer cylinder part 102, and a scraping plate 106 attached to the distal end side of the inner cylinder part 104 contacts the outer peripheral surface of the plunger 34 in the resin discharge hole. The scraping plate 106 is disposed so as to extend parallel to the axial direction of the plunger 34. Therefore, when the plunger 34 rotates in the plunger cylinder 32, the resin adhering to the outer peripheral surface of the plunger 34 is scraped off by the scraping plate 106 and discharged into the inner cylinder portion 104. The scraping plate 106 is not limited to a plate shape, and any shape member (also referred to as a scraping member) may be used as long as it can contact the outer peripheral surface of the plunger 34 and scrape off the molten resin. Good.

  In order to bring the scraping plate 106 into contact with the plunger 34, the inner cylinder portion 104 that supports the scraping plate 106 is provided by a spring (see FIG. 5 or FIG. 6) provided between the outer cylinder portion 102. It is biased in the direction of the plunger 34. Accordingly, the scraping plate 106 is pressed against a part of the outer peripheral surface of the plunger 34, and the molten resin adhering to the plunger 34 can be scraped off by the rotation of the plunger 34.

  Next, the resin removal mechanism 100 of the pre-plastic injection device according to the first embodiment of the present invention will be described with reference to FIG. FIG. 5 is a cross-sectional view of the resin removing mechanism 100 according to the first embodiment of the present invention, and is a cross-sectional view taken along the line VV in FIG.

  In FIG. 5, a horizontal section of the plunger cylinder 32 is shown, and the plunger 34 is located at the center of the plunger cylinder 32. Although the heater 40 is wound around the outer periphery of the plunger cylinder 32, the illustration is omitted. A resin discharge hole 108 is formed in the radial direction of the plunger cylinder 32 with respect to the plunger hole in which the plunger 34 is accommodated, and the tip of the resin discharge hole 108 reaches the plunger hole.

  A taper screw is formed in the vicinity of the entrance portion of the resin discharge hole 108, and a taper screw formed at the tip of the outer cylinder portion 102 is screwed into the taper screw, and the outer cylinder portion 102 is in the axial direction of the plunger cylinder 32. It is fixed vertically.

  On the inner side of the outer cylinder portion 102, a rear portion (side far from the plunger 34) of the inner cylinder portion 104 is movably disposed. On the other hand, the front side (the side facing the plunger 34) of the inner cylinder portion 104 extends into the resin discharge hole 108 beyond the distal end portion of the outer cylinder portion 102. The inner cylinder portion 104 has a hollow cylindrical shape, and a scraping plate 106 is attached to the inside of the tip portion.

  The scraping plate 106 is fixed to the inner side of the inner cylinder portion 104 so that the end portion thereof contacts the outer peripheral surface along the axial direction of the plunger 34. That is, when the inner cylinder portion 104 is urged toward the plunger 34, the end portion of the scraping plate 106 comes into contact with a part of the outer peripheral surface of the plunger 34 exposed in the resin discharge hole 108.

  The urging force to the inner cylinder part 104 is generated by a coil spring 110 as an elastic body disposed between the inner cylinder part 104 and the outer cylinder part 102. That is, the distal end portion of the inner cylinder portion 104 has an outer diameter enough to slide on the inner wall of the resin discharge hole 108, but the outer diameter is smaller than the distal end portion except for the distal end portion. A space is formed between the inner cylinder 104 and the outer periphery of the inner cylinder portion 104. A coil spring 110 is disposed in this space, and one end of the coil spring 110 abuts on the end surface of the outer cylinder portion 102, and the other end abuts on a step portion on the distal end side of the inner cylinder portion 104. The coil spring 110 has such a length that it is disposed in a pre-compressed state, and the force that the coil spring 110 returns becomes the urging force that presses the inner cylinder portion 104 toward the plunger 34. The coil spring 110 as an elastic body is not limited to a coil spring, and may be an elastic body such as rubber or resin.

  Here, the molten resin that has entered the clearance between the plunger 34 and the plunger cylinder 32 gradually moves to a portion where the end portion of the scraping plate 106 contacts the plunger 34. Since the plunger 34 rotates to open and close the resin supply path as described above in the injection process, the molten resin adhering to the outer periphery of the plunger 34 is scraped off by the scraping plate 106 when the plunger 34 rotates, It will accumulate inside the cylinder part 104.

  Therefore, the molten resin that has entered the clearance between the plunger 34 and the plunger cylinder 32 does not adhere to the outer peripheral surface of the plunger 34 for a long time, and carbonization of the molten resin attached to the outer peripheral surface of the plunger 34 is prevented. The normal movement of the plunger 34 in the plunger cylinder 32 can be maintained for a long time.

  In addition, it is desirable to remove the molten resin collected inside the inner cylindrical portion 104, for example, with a frequency of about once a day.

  Here, the rotation of the plunger 34 is normally 180 degrees and is a reciprocating rotational movement. However, if the reciprocating rotation is 180 degrees, only half of the outer circumferential surface of the plunger 34 is in contact with the scraping plate 106. As a result, all the molten resin cannot be scraped off. Therefore, a more preferable result can be obtained by setting the rotation direction of the plunger 34 to one direction. That is, the plunger 34 is rotated 180 degrees for supplying the molten resin, and when the supply of the molten resin is finished, the plunger 34 is rotated 180 degrees in the same direction to block the resin supply path. Thereby, the scraping plate 106 can be brought into contact with the entire outer periphery of the plunger 34, and the molten resin can be scraped over the entire periphery of the plunger 34.

  The plunger 34 is rotated at a position where the plunger 34 is located at the front end and the rear end of the axial movement range (advance / retreat range). For this reason, when the plunger 34 is located in the middle of the moving range, the portion where the scraping plate 106 is in contact with the plunger 34 does not rotate, so the molten resin cannot be scraped off. When the injection process is continuously performed, the resin moves along the plunger 34 to a portion where the scraping plate 106 is in contact with the resin, and can be scraped off. However, when the operation of the injection device is stopped, the resin adhering to the portion before the scraping portion remains as it is. Therefore, when the operation of the injection device is stopped, as a post-process after the operation is stopped, the molten resin remaining on the plunger 34 is scraped off by simultaneously moving the plunger 34 in the axial direction while rotating the plunger 34. It is desirable.

  Next, a resin removing mechanism 100A of a pre-plastic injection device according to a second embodiment of the present invention will be described with reference to FIG. FIG. 6 is a cross-sectional view of the resin removing mechanism 100A according to the second embodiment of the present invention, and corresponds to a cross-sectional view taken along line VV in FIG. The resin removal mechanism 100A in this embodiment is obtained by changing the arrangement position of the coil spring 110 of the resin removal mechanism 100 described above.

  In the resin removal mechanism 100 described above, the difference t between the outer diameter on the distal end side of the inner cylinder portion 104 and the inner diameter of the resin discharge hole 108 may be about 1 mm, for example, due to processing tolerances. In this case, the molten resin adhering to the plunger 34 may enter between the outer peripheral surface of the inner cylinder portion 104 and the inner peripheral surface of the resin discharge hole 108 and gradually enter the space in which the coil spring 110 is accommodated. . In such a state, the molten resin adheres to the coil spring 110 and then hardens or carbonizes, and the coil spring 110 may not function normally.

  Therefore, in the resin removing mechanism 100A according to the present embodiment, the coil spring 110A is disposed at a position far from the plunger 34, and the molten resin does not easily enter the space in which the coil spring 110A is accommodated. The structure of the resin removal mechanism 100A will be described below in comparison with the resin removal mechanism 100 described above.

  In the resin removal mechanism 100A, the distal end portion of the outer cylinder portion 102A extends to the depth of the resin discharge hole 108, and the inner cylinder portion 104A is not provided with a portion having a large outer diameter. The rear end of the inner cylinder portion 104A extends so as to protrude from the rear end of the outer cylinder portion 102A. A portion having a small outer diameter is formed at the rear end portion of the inner cylindrical portion 104A, and a space is formed between this portion and the inner peripheral surface of the outer cylindrical portion 102A. A coil spring 110A is accommodated in this space. The spring retainer 112 that contacts the rear end of the coil spring 110A is fixed in a state of being fitted to the outer periphery of the outer cylindrical portion 102A.

  The resin removing mechanism 100A having the above-described configuration can scrape the molten resin adhering to the plunger 34 with the scraping plate 106 in the same manner as the resin removing mechanism 100, and can obtain the same effect as the resin removing mechanism 100.

  Further, the space in which the coil spring 110A is accommodated is at a position away from the plunger 34, and the possibility that the molten resin enters the space in which the coil spring 110A is accommodated is reduced. Furthermore, since both the outer cylindrical portion 102A and the inner cylindrical portion 104A are small machined parts, the clearance between the inner peripheral surface of the outer cylindrical portion 102A and the outer peripheral surface of the inner cylindrical portion 104A is, for example, 0.2 mm. It can be a clearance of a degree. Thereby, the possibility that the molten resin enters the space in which the coil spring 110A is accommodated through the clearance between the inner peripheral surface of the outer cylindrical portion 102A and the outer peripheral surface of the inner cylindrical portion 104A is further reduced. Therefore, there is almost no possibility that the molten resin adheres to the coil spring 110A and does not function. If the molten resin enters the space in which the coil spring 110A is accommodated through the clearance between the inner peripheral surface of the outer cylindrical portion 102A and the outer peripheral surface of the inner cylindrical portion 104A, the spring retainer 112 is removed. Only the coil spring 110A and the inner cylinder portion 104A can be easily removed, and the molten resin can be easily removed.

  In the above resin removal mechanisms 100 and 100A, the position of the scraping plate 106 may be changed to the position shown in FIG. 7 or FIG.

  The scraping plate 106 shown in FIG. 7 is provided so as to incline in the rotation direction of the plunger 34 (indicated by an arrow in the figure), and can scrape off the molten resin adhering to the plunger 34. It is possible to scrape the resin efficiently.

  The scraping plate 106 shown in FIG. 8 is disposed at a position shifted to the downstream side in the rotation direction of the plunger 34 (indicated by an arrow in the figure), and can take a large space for collecting the scraped molten resin. It is possible to scrape the resin efficiently.

  In the above-described resin removing mechanisms 100 and 100A, the shape of the end portion of the scraping plate 106 that contacts the plunger 34 may be a straight line, but as shown in FIG. By making the curved shape into a curved shape, it is possible to prevent the rotation of the plunger 34 from being hindered without applying a large load to the plunger 34 when the scraping plate 106 is pressed against the plunger 34. Alternatively, when the scraping plate 106 is brought into contact with the tapered portion 34d of the plunger 34 shown in FIG. 4, as shown in FIG. 9B, the end portion of the writing scraping plate 106 that contacts the plunger 34 is tapered. It is good also as a shape which inclines along 34d.

It is sectional drawing which shows the injection apparatus of the prep plastic type injection apparatus to which this invention was applied. It is sectional drawing which shows the injection apparatus of the prep plastic type injection apparatus to which this invention was applied. It is an enlarged view of the plunger shown in FIG. It is an enlarged view of the plunger provided with the taper part. It is sectional drawing of the resin removal mechanism by 1st Example of this invention. It is sectional drawing of the resin removal mechanism by 2nd Example of this invention. It is sectional drawing of the resin removal mechanism provided with the inclined scraping board. It is sectional drawing of the resin removal mechanism provided with the scraping board shifted in position. It is a figure which shows the modification of a scraping board.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Resin plasticizing apparatus 12 Plasticizing cylinder 14 Screw 30 Resin injection apparatus 32 Plunger cylinder 32c Resin inflow hole 34 Plunger 34a Groove part 34b Spline part 34c Small diameter part 34d Taper part 36 Nozzle part 60 Plunger drive part 66 Injection motor 88 Seal opening / closing motor 100, 100A Resin removal mechanism 102, 102A Outer cylinder part 104, 104A Inner cylinder part 106 Scraping plate 108 Resin discharge hole 110, 110A Coil spring 112 Spring retainer

Claims (7)

A pre-plastic injection device having a resin injection device for injecting molten resin supplied from a resin plasticizing device,
The resin injection device is
A plunger configured to be rotatable in the plunger cylinder;
A resin discharge hole formed in the plunger cylinder, in which a part of the outer peripheral surface of the plunger is exposed;
A scraping member provided in the resin discharge hole and extending in the axial direction of the plunger ;
Possess an elastic member for biasing the scraping member to the plunger,
The pre-plastic injection device , wherein the scraping member is included in a resin removing mechanism attached to the plunger cylinder . The pre-plastic injection device according to claim 1,
The pre-plastic injection device, wherein the scraping member is arranged in at least one of a state inclined with respect to the outer peripheral surface of the plunger and a state shifted from the center of the resin discharge hole. The pre-plastic injection device according to claim 1,
The pre-plastic injection device, wherein an end of the scraping member that contacts the plunger has a convex shape or an inclined shape. The pre-plastic injection device according to claim 1,
A pre-plastic injection device comprising means for moving the plunger in the axial direction while rotating the plunger. The pre-plastic injection device according to claim 1,
The pre-plastic injection device, wherein the plunger has a small-diameter portion having an outer diameter smaller than an outer diameter of a tip portion, and the scraping member abuts on an outer peripheral surface of the small-diameter portion. A pre-plastic injection device according to claim 5 ,
The small diameter portion of the plunger is connected to the tip portion of the plunger by a step, and the scraping member abuts on the outer peripheral surface of the small diameter portion in the vicinity of the step. apparatus. A pre-plastic injection device according to claim 5 ,
A pre-plastic injection device, wherein a taper portion is provided between the small diameter portion of the plunger and the tip portion of the plunger, and the scraping member abuts on an outer peripheral surface of the taper portion.

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