JP3714421B2 - Injection mold equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an injection mold apparatus used for injection molding of a molded product such as an impeller of a fuel pump that supplies fuel to an engine.
[0002]
[Prior art]
The impeller of this type of fuel pump that has been used in the past is formed in the shape of a disk and is injection-molded with a thermoplastic engineering plastic that has excellent heat resistance, dimensional stability, mechanical properties, moldability, etc., such as PPS resin. Is formed. The outer periphery of the impeller, which is an injection molded product, has a material size, for example, a diameter of 33.6 mm, an accuracy of ± 0.05 mm, and a thickness of, for example, 4.05 mm, with an accuracy of ± 0. High accuracy of .05 mm is required. Further, a plurality of intersecting and bi-directionally inclined V-shaped blade groups are formed on both the front and back surfaces of the inner edge of the impeller, and the level difference at the intersection of these blade groups is about 0.05 mm (50 microns). It is required to be highly accurate. For this reason, it is indispensable to injection mold a highly accurate molded product while maintaining extremely high mold accuracy.
[0003]
Further, when the PPS resin or the like constituting the injection molded product is melted at a high temperature (for example, about 320 ° C.), a gas is generated from the molten resin, and the gas is injected when the gas is released into the cavity in the mold. While being caught in the molded product, the accuracy of the injection molded product is remarkably lowered, and it adheres to the inner wall of the cavity in the mold and further reduces the accuracy of the injection molded product. Further, the gas adhered to the inner wall of the cavity is scaled, often necessitating the cleaning of the mold and reducing the life of the mold.
[0004]
Furthermore, if the residual air in the mold cavity is not evacuated and vacuumed before injection molding, the residual air in the cavity is adiabatically compressed when injected into the molten resin mold cavity. It had an adverse effect on the accuracy of injection molded products.
[0005]
Therefore, conventionally, a gap (air vent groove) called an air vent is provided in a part of a mold for molding a normal injection molded product, and residual gas / air in the cavity is removed from the gap using a vacuum pump. Some have been inhaled to escape from the cavity of the mold (see, for example, Patent Document 1).
[Patent Document 1]
JP-A-4-129716 (the third page, upper right column, line 5 to the same page, lower right column, line 15; FIGS. 3 and 4).
[0006]
[Problems to be solved by the invention]
However, in the conventional injection mold apparatus as described above, the mold is provided with an air vent (gap) and an exhaust path opening / closing pin linked to opening / closing of the mold between the vacuum suction cylinder and the mold cavity. In connection with the mold closing operation, an exhaust passage opening / closing pin is provided so that the gas in the cavity is sucked into the suction cylinder from only one place.
[0007]
Therefore, since the gas in the mold cavity is only sucked from only one place after the mold is closed, the gas is not completely vented from the cavity, so the accuracy of injection molding is low. Further, it is often necessary to remove the scale caused by the gas adhering to the inner wall of the cavity, so that the life of the mold is remarkably short (for example, about 5 hours).
[0008]
Therefore, the present invention has been made to solve such problems of the conventional injection mold apparatus. Even after the air vent valve is closed due to the injection pressure of the molten resin, the present invention is always applied from within the mold cavity. Air venting and gas venting are performed through minute air vent grooves and air vent holes so that high-precision, high-quality injection-molded products can be molded with high productivity and high yield, and the life of the mold to be used An object of the present invention is to provide an injection mold apparatus capable of remarkably improving the above.
[0009]
[Means for Solving the Problems]
The present invention provides an injection mold apparatus in which a vacuum exhaust source and a cavity of a mold apparatus are communicated with each other via an air vent valve and a first air vent hole that are closed by an injection pressure, and the cavity and the second air are communicated. The punch hole communicates with the movable mold member, which is a contact surface between the fixed mold member and the movable mold member, through a fine gap formed close to the cavity, and the injection pressure causes the Even after the air vent valve is closed, gas can be vented from the cavity through the fine gap.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of an injection mold apparatus of the present invention will be described with reference to the accompanying drawings.
[0011]
First, FIGS. 1 and 2 show an injection molding apparatus in which an injection mold apparatus of the present invention is mounted and an injection molded product (for example, an impeller of a fuel pump) is molded.
[0012]
The injection molding apparatus 1 is installed on the floor surface FL through vibration-proof rubber or the like, and moves horizontally on the main body of the injection molding apparatus 1 so that the injection port is a sprue bush (described later) of the injection molding apparatus 3. The injection cylinder head 2 for introducing the melted PPS resin into the mold, the operation screen device 4 for monitoring the injection molding operation, and the hopper 5 for supplying the particulate PPS resin into the injection head 2. A chute 6 for storing an injection molded product taken out from the injection mold, a control panel 7 storing control equipment for the injection molding apparatus 1 as a whole, and an injection molding apparatus 3 for attaching the injection molding apparatus 3 to the injection molding apparatus 1 4 The tie bar 8 is configured to perform a predetermined injection molding operation.
[0013]
Next, the injection mold apparatus 3 of the present invention will be described with reference to FIGS.
[0014]
FIG. 3 shows a state in which the injection mold apparatus 3 of the present invention is closed, and the mold apparatus 3 is composed of a fixed mold member A and a movable mold member B.
[0015]
As shown in FIG. 3, the fixed-side mold member A is fixed to, for example, a fixed-side mounting plate 31 fixed to four tie bars 8 (see FIGS. 1 and 2), and the fixed-side mounting plate 31. From the runner lock pin 39, the fixed side mounting plate 31 through which the runner lock pin 39 is inserted, the runner stopper 32 mounted, and the fixed side mold plate 33 that contacts the runner stopper 32 and mold clamping (when closed). Become. A sprue bush 37 for introducing the molten resin into the cavity C in alignment with the nozzle (injection port) of the injection head 2 is attached to the fixed side attachment plate 31 via a locating ring 36. In the present embodiment, the mold member has two cavities provided with two cavities C (see FIGS. 4 and 5).
[0016]
The fixed side template 33 includes a runner plate 38 having a runner portion R communicating with the sprue bush 37 and a gate G (for example, three pieces) branched from the runner portion R at a right angle and communicated with the cavity C and the runner portion R. And an air vent valve 41 for exhausting air from the cavity C is provided. The air vent valve 41 is fluidly connected to a vacuum pump (not shown) through, for example, two air vent holes 63, and is closed by an injection pressure at the time of injection molding, and opened when the pressure is released. ing.
[0017]
That is, as shown in FIG. 6, the air vent valve 41 is disposed in the flow path between the runner R and, for example, the two first air vent holes 63. The air vent valve 41 is a commercially available product (for example, an air vent valve manufactured by System Resources Co., Ltd.), and a slide piece 41a is urged into a case 41b by a coil spring 41c and is placed on an upper inner wall in the case 41b. It contacts normally and forms a gap g for degassing between the slide piece 41a and the wall surface of the case 41b. Before injection of the molten resin (when the mold is closed), the remaining in the cavity C from the cavity C and the runner R to the first air vent hole 63 via the air vent holes 41d and 41e formed in the air vent valve 41. Air can be vented. Further, when the molten resin is injected into the cavity C and the runner part R, the slide piece 41a slides downward against the spring pressure of the coil spring 41c as shown in FIG. It is comprised so that the clearance gap g may be closed.
[0018]
Further, as shown in FIG. 3, a second fixed side insert 35 is rotatably disposed on the fixed side mold plate 33 via a fixed side bearing (for example, a single row deep groove bearing) 40. In the second fixed side insert 35, a first fixed side insert 34 having a concentrically different diameter is mounted. The second fixed side insert 35 is provided with a recess that forms one half of the cavity C.
[0019]
On the other hand, as shown in FIG. 3, the movable side mold member B is guided by, for example, four guide pins 70 and moved in the horizontal direction by a driving device (not shown) to open and close the mold member. A lower ejector plate 51 in which a plurality of ejector pins 64 are arranged side by side, an upper ejector plate 52 for guiding the ejector pins 64, first and second movable side receiving plates 54 and 55, and a movable side mounting plate 50. Movable side spacer 53 sandwiched between first movable side receiving plate 54 and movable corresponding to a mold mounted on second movable side receiving plate 55 via a plurality of coil springs 61 and backing plate 62. And a side mold plate 56. The movable side mold plate 56 is always urged in the mold clamping direction by, for example, four coil springs 61. Further, the first movable side receiving plate 54 is attached to the movable side mounting plate 50 by a fastening bolt 75. Further, a return pin 75 is attached to the movable side mounting plate 50 to assist in returning the lower and upper ejector plates 51 and 52.
[0020]
Further, as shown in FIG. 3, a third movable side nest 59 is rotatably disposed on the movable side mold plate 56 via a movable side bearing (single row deep groove bearing) 60. The second movable side insert 58 having a different diameter is fitted inside the third movable side insert 59, and further, the ejector pin 64 is inserted into the second movable side insert 58 with a different diameter. A first movable side insert 57 is inserted. Here, the half part of the cavity C which forms the blade groove of the injection molded product (impeller) is engraved on the second movable side insert 58. Further, an extrusion lot rod 65 is fixed to the lower ejector plate 51, and the extrusion lot rod 65 is further tightened in a mold clamping direction by a pressurizing device (not shown), and a molded product after injection molding is ejected by an ejector pin 64. Is configured to be extruded and compressed. Further, as shown in FIG. 3, a lock pin 73 is fixed to the second movable side receiving plate 55 to prevent the movable side mold plate 56 from being taken away to the lock fixing side during the movement, and the coil spring 61 By urging, the template 56 is moved in the releasing direction, and the detent of the third movable side insert 59 is released.
[0021]
Furthermore, in the injection mold apparatus 3 of the present invention, as shown in FIG. 4, the stationary mold plate 33 and the movable mold plate 56 slide horizontally with, for example, four guide pins 70. A guide bush 71 for guiding in the direction and a bar heater 72 for constantly heating the mold to about 150 ° C. are provided.
[0022]
Here, as shown in FIG. 3, the protrusion 59a of the third movable side insert 59 is connected to the outer peripheral portion 10 of the injection-molded product, and the protrusion 35a of the second fixed side insert 35 and the second movable side insert. The protrusion 58a of the 58 is a blade groove, and the insert pin 57b is inserted between the first movable side insert 57 and the protrusion pin 57a. The projecting pin 57a of the first movable side insert 57 forms the shaft hole 14 respectively. In addition, an annular air vent groove 35b having a depth of about 0.3 mm is formed at a position adjacent to the outer periphery of the cavity C of the second fixed side insert 35 and in contact with the first movable side insert 58. It is provided and communicates with the second air vent hole 80 through the air vent hole 35c (see FIG. 8).
[0023]
That is, as shown in detail in FIGS. 4 and 6, particularly FIGS. 7 and 8, the annular stepped portion 35 e outside the protruding portion 35 a of the second fixed side insert 35 that is the fixed mold member A. An annular air vent groove 35b is formed in the end surface of the runner plate 38, and an annular air vent groove 38a is formed in the left end surface of the runner plate 38 so as to penetrate through the second fixed side insert 35. The hole 35c is in fluid communication with the annular air vent groove 35b. Further, the annular air vent groove 38 a communicates with the second air vent hole 80 via a linear air vent groove 38 b formed in the runner plate 38.
[0024]
On the other hand, as shown in detail in FIG. 8, on the right end surface of the third movable side insert 59 that is the movable side mold member B, the annular air vent groove 59a is located at a position facing the annular air vent groove 35b. And an annular air vent groove 59c having a depth of about 0.3 mm and having a depth of about 0.3 mm and another annular fine gap (air vent groove) having a depth of about 25 μm and a width of about 0.6 mm. It communicates with the cavity C through 59e. As shown in detail in FIG. 5, the annular minute gap 59e communicates with the annular air vent groove 59a via the linear air vent grooves 59f and 59d and also communicates with the air vent hole 35c. Further, the annular air vent groove 59a is in fluid communication with the first air vent hole 63 and the second air vent hole 80, respectively.
[0025]
Next, the operation of the embodiment of the injection mold apparatus of the present invention configured as described above will be described.
[0026]
First, as shown in FIG. 3, the movable mold member B, in particular, the movable side mounting plate 50 is moved along the guide pins 70 in the direction of the fixed side mold member A, in particular, the fixed side mounting plate 31 by a driving device (not shown). Move to close mold and clamp. At this time, a cavity C corresponding to the shape of the injection molded product is formed in the mold. In this mold-clamped state, PPS resin that is heated to a temperature of about 320 ° C. in the injection head 2 (see FIG. 1) and is in a molten state is introduced from a sprue bush 37 that is fixed to the fixed-side mounting plate 31. The injection molded product (impeller) is injection-molded by injection into the cavity C through the runner portion R in the runner plate 38 and the gate G in the first fixed side insert 34. At this time, the fixed mold member A and the movable mold member B are heated to a temperature of about 150 ° C. by the bar heater 72. Before the injection molding, the air vent valve 41 is opened, air is vented from the cavity C and the runner portion R, and the remaining air is evacuated to the outside through the air vent hole 63. At the time of injection molding, the air vent valve 41 of the runner part R is closed by the injection pressure, but as will be described later, the other air vent circuits continue to operate and evacuate to the end.
[0027]
That is, when molten resin is injected from the sprue bush 37 into the cavity C of the mold apparatus through the runner part R and the gate G, the slide piece 41a of the air vent valve 41 is moved by the injection pressure as shown in FIG. It slides downward against the spring force of the coil spring 41c, closes the air vent gap g shown in FIG. 6, and prevents air vents from the cavity C, the runner part R and the gate G. However, at this time, the cavity C still remains via the annular fine gap 59e, the annular air vent grooves 59a, b, c, the air vent hole 35c, the annular air vent groove 38a, and the linear air vent groove 38b shown in FIG. , Respectively, communicate with the second air vent hole 80. Therefore, even after the air vent valve 41 is closed, the air venting and gas venting from the cavity C continues until the final stage of the injection molding process, and the annular fine gap 59e and the many air vent grooves and air described above. This is done with a vent hole. By this air vent, the gas generated from the molten resin is completely excluded from the cavity C, so that no gas is mixed into the molded product, and the generated gas is not seized on the mold. The lifespan of this product is dramatically improved. For example, the life of a conventional mold apparatus having a normal air vent valve is about 5 hours (about 1,000 pieces), but the mold apparatus of the present invention is about 72 hours (about 13,000 pieces). ) Greatly improved.
[0028]
Then, after a predetermined time, the extrusion lot rod 65 (see FIG. 3) is actuated by a pressurizing device to compress a minute amount in the mold clamping direction, the ejector pin 64 is moved, and this compression improves the processing accuracy of the injection molded product. Improve.
[0029]
Next, a driving device (not shown) is operated to move the movable mold member B shown in FIG. 3 along the guide pins 70 to perform mold opening. The fixed side mold plate 33 is connected to the movable side mold member 13 by a parting lock (not shown) and separated from the runner stopper 32 fixed by the mold opening. At this time, the runner portion R and the gate G formed by curing the molten resin are attached to the runner stopper 32 side. On the other hand, the cured injection-molded product remains in the cavity C formed by contacting the second movable side insert 58 and the second fixed side insert 35 of the movable mold member B.
[0030]
Further, when the mold opening is continued, the movable side mold plate 56 is separated from the fixed side mold plate 33 by releasing the parting lock (not shown). At this time, due to the movement of the fixed side mold plate 33 in the axial direction, a component force in the circumferential (rotational) direction acts on the slope of the V-shaped blade of the injection molded product (impeller), and the second fixed side insert 35 Tries to rotate in the circumferential direction by about 2 mm. At this time, this rotation is due to a component force acting in the direction of the inclined surface of the impeller blade groove, and this direction may be clockwise or counterclockwise. In particular, in the injection mold apparatus 3 of the present invention, a bearing 40 such as a single row deep groove bearing is fitted on the outer periphery of the rotating second fixed side insert 35. While the child 35 rotates very smoothly, the child 35 moves away from the second movable-side insert 59, and is separated from the V-shaped blade groove of the injection molded product, so that the insert 35 can be easily removed.
[0031]
Further, when the mold opening is continued, the hardened runner portion R and the gate G shown in FIG. 3 are detached from the runner stopper 32. Then, due to the movement of the movable side mold member B by the axial opening, a circumferential (rotational direction) component force acts on the slope of one V-shaped blade groove of the injection molded product, and this component force Thus, the second movable side nest 59 is smoothly rotated in the circumferential direction by, for example, about 2 mm with the help of the movable side bearing 60 in the circumferential direction. By this rotational movement, the second movable side insert 59 is completely detached from one of the V-shaped blade grooves of the injection molded product, and the mold release of the injection molded product M is completed.
[0032]
Thereafter, the above-described steps are repeated to sequentially form injection molded products.
[0033]
【The invention's effect】
According to the injection mold apparatus of the present invention, since air venting and gas venting from the mold cavity are completely performed even after the molten resin injection, the life of the mold is greatly improved, The mixing of the gas molded product is eliminated, and the productivity, yield, and molding accuracy of this type of injection molded product are significantly improved.
[Brief description of the drawings]
FIG. 1 is a front view of an injection molding apparatus equipped with an injection mold apparatus of the present invention.
FIG. 2 is a plan view of the injection molding apparatus shown in FIG.
FIG. 3 is a partially broken cross-sectional view of the injection mold apparatus of the present invention shown in FIG. 1 as viewed from the direction of arrows ZZ, showing a state in which the injection mold is closed.
4 is a front view of a fixed mold member of the injection mold apparatus of the present invention shown in FIG. 3 as viewed from the direction of arrows II.
5 is a front view of the movable mold member of the injection mold apparatus of the present invention shown in FIG. 3 as viewed from the direction of arrows II-II.
6 is a partially enlarged longitudinal sectional view taken along the line III of the injection mold apparatus of the present invention shown in FIG.
7 is a partially enlarged vertical cross-sectional view taken along the line IV of the injection mold apparatus of the present invention shown in FIG.
8 is a partially enlarged longitudinal sectional view of an air vent portion of the injection mold apparatus of the present invention shown in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Injection molding apparatus 2 Injection cylinder head 3 Mold apparatus 4 Operation screen apparatus 5 Hopper 6 Chute 7 Control panel 8 Tie bar 31 Fixed side mounting plate 32 Runner stopper 33 Fixed side mold plate 34 First fixed side insert 35 Second fixed side Insert 35a Protruding portion 35b Annular air vent groove 35c Air vent hole 37 Sprue bush 38 Runner plate 38a Annular air vent groove 38b Linear air vent groove 40 Fixed side bearing 41 Air vent valve 41a Slide piece 41b Case 41c Coil spring 50 Movable side Mounting plate 56 Movable side mold plate 56a Linear air vent groove 57 First movable side insert 58 Second movable side insert 59 Third movable side insert 59a Annular air vent groove 59b Linear air vent groove 59c Annular air vent groove 59d Straight air vent groove 59e Annular minute gap 0 movable bearing 63 the first air vent hole 70 guide pin 80 second air vent hole A fixed die member B movable mold member C cavity G gate R runner section

Claims (1)

In the injection mold apparatus, the mold cavity is communicated with the air vent valve and the first air vent hole for closing the cavity of the mold by the injection pressure and communicated with the vacuum exhaust source, and the stationary mold member and the movable side the movable mold member located on the abutment surface of the mold member in proximity to the cavity engraved annular fine gap, further communicates a plurality of first linear air vent grooves in the annular fine gap Further, the first linear air vent groove communicates with the annular air vent groove, and the plurality of second linear air vent grooves communicate with the annular air vent groove , and the fixed side mold plate and the movable side mold plate communicating said second linear vent grooves into a plurality of second air vent hole formed in, communicates with the said cavity second air vent hole in the evacuation source, the air vent Bal by injection pressure Even after closing, injection mold apparatus characterized by through the annular fine gap and the plurality of second air vent holes to allow venting from the cavity.

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