JP3897455B2 - Injection mold - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an injection mold capable of simultaneously molding two types of molded products having different shapes with one mold.
[0002]
[Prior art]
An injection mold for molding a molded product is provided with a plurality of cavities in one molding mold, distributes molten resin injected from a molten resin injection port, and guides it to a gate communicating with the cavity in a heat-retaining state. It is configured as follows.
[0003]
This injection mold is configured so that a plurality of molded products can be molded simultaneously by one injection molding. Basically, one molten resin injection port is provided in the sprue portion provided in the center portion. And a branch passage that branches into a plurality of branches in communication therewith. On the other hand, the mold body is provided with a plurality of cavities, and a plurality of nozzle holder units having gates communicating with the cavities. Further, a hot runner manifold having a heater is connected to communicate the branch passage of the sprue portion and each nozzle holder unit, and the injected molten resin is guided in a heat-retaining state.
[0004]
Accordingly, the molten resin injected from the molten resin injection port is distributed to a plurality of runners via the branch passages, led from these runners to the gate via the plurality of nozzle holder units, and further injected from the gate to each cavity. The
[0005]
[Problems to be solved by the invention]
However, an injection mold generally molds one or a plurality of molded products at the same time, and it is not known that a molded product having different shapes can be molded simultaneously with one mold.
[0006]
The present invention has been made paying attention to the above circumstances, and an object of the present invention is to provide an injection mold that can simultaneously mold molded products having different shapes with one mold.
Another object is to provide an injection mold that can prevent resin leakage from the molten resin passage during and after injection molding.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, claim 1 includes a fixed mold 2, a movable mold 3 that can be brought into and out of contact with the fixed mold 2, and the fixed mold 2 and the movable mold 3. Between the fixed mold 2 and the split mold 4 and between the fixed mold 2 and the fixed mold. This is an injection mold in which a first cavity 8 and a second cavity 11 having different shapes are provided between the mold 2 and the movable mold 3, respectively, and molded products having different shapes are simultaneously molded by one mold. The fixed mold 2 has a resin injection port, a resin passage 14 communicating with the resin injection port, and a first gate 15 communicating with the resin passage 14 and guiding the molten resin to the first cavity 8. , The gate pin 17 that opens and closes the first gate 15, and the resin passage 14 communicates and melts. Opening the split surface 20 of the split molds 4 of the fixed mold 2 in order to guide the fat into the second cavity 11, and a second freely advance and retreat in the axial direction 1 of the sprue bush 21, the first It is interpolated in the sprue bush 21, and a second freely advance and retreat in the axial direction 1 of the valve pin 22 retracts the first valve pin 22 causes advancing the first sprue bushing 21 to the split in four directions at the time of injection A first drive mechanism 24 that opens the gate 23 of the first sprue bush 21 is provided.
[0008]
The split mold 4 has a second sprue bush 31 having a gate 32 facing the first sprue bush 21, and a molten resin that communicates with the second sprue bush 31 to the second cavity 11. An open gate 35 for guiding, an internal pressure removing pin 37 inserted in the second sprue bush 31 so as to be movable back and forth in the axial direction, a second valve pin 38 for opening and closing the gate 32, and a second valve pin after injection 38 is advanced to close the gate 32, and the internal pressure removing pin 37 is retracted to provide the second drive mechanism 40 for removing the internal pressure of the second sprue bushing 31.
[0009]
According to a second aspect of the present invention, the first drive mechanism 24 of the first aspect includes a first hydraulic cylinder 25 provided in the fixed mold 2 and the first hydraulic cylinder 25 provided in the first hydraulic cylinder 25. A first piston 26 for driving the sprue bushing 21, a second hydraulic cylinder 27 provided in the first piston 26, and driving the first valve pin 22 provided in the second hydraulic cylinder 27. And the second piston 28.
[0010]
According to a third aspect of the present invention, the second drive mechanism 40 according to the first aspect includes a moving block 41 provided in the split mold 4 and capable of moving back and forth in a direction orthogonal to the advancing / retreating direction of the internal pressure removing pin 37, provided, characterized by being configured from the inclined surface 43 for advancing and retracting the cam groove 42 and the internal pressure is removed the pin 37 for opening and closing the gate 32 is advance and retreat the second valve pin 38 by the forward and backward movement of the movable block 41.
[0011]
According to the above-described configuration, the divided surfaces of the divided first and second sprue bushings can be prevented from leaking resin from the divided surface because the surface pressure is increased at the time of injection. Since the internal pressure of the bush is lowered, resin leakage from the open gate can be prevented.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 is a longitudinal side view of an injection mold, FIG. 2 is a plan view thereof, FIG. 3 is a sectional view taken along line AA in FIG. 2, and FIG. 4 is a sectional view taken along line BB in FIG. . As shown in FIGS. 1 to 4, the injection mold 1 includes a fixed mold 2, a movable mold 3 that can come in contact with and away from the fixed mold 2, and a split mold that can come in contact with and away from the movable mold 3. 4. In this embodiment, the injection mold 1 is provided with a first molding part 1A and a second molding part 1B, which have the same structure, and therefore the first molding part 1A will be described.
[0013]
The movable mold 3 is provided with a truncated cone-shaped core portion 5, and the core portion 5 is fitted in a conical hole 7 provided in a slide block 6 constituting the split mold 4. A first cavity 8 is provided between the top of the core portion 5 and the dividing surface of the fixed mold 2. The first cavity 8 is dish-shaped and has a flange on the outer peripheral surface.
[0014]
A step portion 9 is formed at the base end portion of the core portion 5, and an annular divided block 10 constituting the split mold 4 is provided around the step portion 9 so as to surround it. A second cavity 11 is provided between the step portion 9 of the core portion 5 and the divided block 10. The second cavity 11 has a cylindrical shape with openings at both ends, and has a large diameter portion and a small diameter portion. Therefore, the first and second cavities 8 and 11 are coaxial with the axis of the core portion 5 and are provided apart from each other in the axial direction of the core portion 5. Reference numeral 12 denotes an ejector pin.
[0015]
A first hot runner 13 is provided on the fixed mold 2 located on the axis of the core portion 5. The first hot runner 13 communicates with a resin passage 14 that communicates with a resin injection port (not shown). The first hot runner 13 is provided with a first gate 15 for guiding the molten resin to the first cavity 8, and the first gate 15 is provided with a gate pin 17 for opening and closing the gate portion 16. Is connected to a hydraulic piston mechanism 18.
[0016]
A second hot runner 19 that communicates with the resin passage 14 is provided at a portion of the fixed mold 2 that faces between the first and second molding portions 1A and 1B. The second hot runner 19 includes a first sprue bush 21 that is movable in the axial direction and opens in the dividing surface 20 of the fixed mold 2 and the split mold 4 to guide the molten resin to the second cavity 11. Is provided. Further, the first sprue bushing 21 interpolated retractably first valve pin 22 in the axial direction, so that the can open and close the gate 2 3.
[0017]
The fixed mold 2 located on the base end side of the first sprue bush 21 and the first valve pin 22 is provided with a first drive mechanism 24 for driving the first sprue bush 21 and the first valve pin 22. Yes.
[0018]
The first drive mechanism 24 includes a first hydraulic cylinder 25 having a recessed portion provided in the fixed mold 2 and a first integral with the first sprue bush 21 provided in the first hydraulic cylinder 25. Piston 26, a second hydraulic cylinder 27 having a recessed portion provided in the first piston 26, and a second piston provided in the second hydraulic cylinder 27 and connected to the first valve pin 22. 28. Further, a first hydraulic circuit 29 for driving the first and second pistons 26 and 28 and a second hydraulic circuit 30 for driving the second piston 28 forward are provided.
[0019]
A second sprue bush 31 is provided on the second hot runner 19 and the slide block 6 of the split mold 4 positioned on the axis. The second sprue bush 31 has a vertical portion 33 having a gate 32 that opens to the dividing surface 20 of the slide block 6 with the fixed mold 2, and a bent portion 34 that is bent laterally from the vertical portion 33. . The bent portion 34 is provided in the divided block 10 and communicates with an open gate 35 that guides the molten resin to the second cavity 11. That is, the open gate 35 is provided on the outer side of the second cavity 11, and the molten resin is injected from the outer side of the second cavity 11, bypassing the core part 5.
[0020]
The slide block 6 positioned on the extension of the vertical portion 33 of the second sprue bush 31 is provided with a through hole 36 coaxially with the vertical portion 33. An internal pressure removing pin 37 is provided in the through hole 36 so as to be able to advance and retreat in the axial direction, and a tip portion of the internal pressure removing pin 37 is inserted into the vertical portion 33 of the second sprue bush 31.
[0021]
Further, a second valve pin 38 is inserted in the internal pressure removing pin 37 so as to be movable forward and backward in the axial direction, and opens and closes the gate 32. Further, the base end portions of the internal pressure removing pin 37 and the second valve pin 38 protrude into a guide hole 39 formed of a cavity continuously provided in the slide block 6 and the fixed mold 2, and the first end portion provided in the guide hole 39. Two drive mechanisms 40 are connected.
[0022]
The second drive mechanism 40 has a moving block 41 provided in the guide hole 39 so as to be able to advance and retreat in a direction orthogonal to the internal pressure removing pin 37, and this moving block 41 is provided by a cylinder 47 provided in the fixed mold 2. It is movable. A cam groove 42 that inclines toward the dividing surface 20 toward the tip is provided at the tip of the moving block 41, and an inclined surface 43 that inclines away from the dividing surface 20 toward the tip. ing. The cam groove 42 engages with an engagement protrusion 44 provided at the base end portion of the second valve pin 38, and the inclined surface 43 has a slider 45 provided at the base end portion of the internal pressure removing pin 37. In contact. Reference numeral 46 denotes an inclined guide pin provided on the fixed mold 2 so as to guide the slide block 6 of the split mold 4.
[0023]
Next, the operation of the first embodiment will be described.
When molten resin is injected from the injection molding machine into the injection mold 1 through the resin injection port, the molten resin is guided to the first hot runner 13 and the second hot runner 19 through the resin passage 4. Here, when the gate pin 17 is retracted by driving the hydraulic piston mechanism 18, the gate portion 16 of the first gate 15 is opened, and molten resin is injected into the first cavity 8 and filled.
[0024]
On the other hand, when the hydraulic pressure is applied from the first hydraulic circuit 29 to the first hydraulic cylinder 25, the first hydraulic piston 26 moves forward and the first sprue bush 21 moves forward. The front end surface presses the end surface of the second sprue bush 31 to apply surface pressure. Therefore, resin leakage from the dividing surface 20 can be prevented. At the same time, since hydraulic pressure is applied from the first hydraulic circuit 29 to the second hydraulic cylinder 27, the second hydraulic piston 28 moves backward, the first valve pin 22 moves backward, and the gate portion 23 opens. .
[0025]
Accordingly, the molten resin in the second hot runner 19 is injected and filled into the second cavity 11 via the open gate 35 via the vertical portion 33 and the bent portion 34 of the second sprue bush 31.
[0026]
When the first cavity 8 and the second cavity 11 are filled with the molten resin in this way, the gate pin 17 is advanced by the hydraulic piston mechanism 18 to close the gate portion 16 of the first gate 15. Further, the second hydraulic piston 27 is advanced by the hydraulic pressure from the second hydraulic circuit 30, the first valve pin 22 is advanced, and the gate portion 23 is closed.
[0027]
Further, as shown in FIG. 5, when the moving block 41 is moved backward by the cylinder 47, the engaging protrusion 44 engaged with the cam groove 42 moves in the direction of the dividing surface 20, so that the second valve pin 38 moves forward. To close the gate 32. At the same time, the inclined surface 43 that has been in contact with the slider 45 moves in the downward gradient direction, so that the internal pressure removing pin 37 integrated with the slider 45 is retracted by the internal pressure of the second sprue bush 31. Since the volume in the second sprue bush 31 is expanded by the retreat of the internal pressure removing pin 37, it is possible to prevent the internal pressure from decreasing and the molten resin in the second sprue bush 31 from leaking from the open gate 35.
[0028]
After the molten resin filled in the first cavity 8 and the second cavity 11 is cooled and solidified, the movable mold 3 moves backward with respect to the fixed mold 2 and the split mold 4 as shown in FIG. Are guided by the inclined guide pins 46 and slid in the horizontal direction to be divided. Therefore, the molded products 8a and 11a are obtained from the first cavity 8 and the second cavity 11, and two types of molded products 8a and 11a having different shapes can be molded simultaneously.
[0029]
In the above embodiment, the mold for simultaneously molding the dish-shaped molded product 8a and the annular molded product 11a has been described, but the present invention is not limited to the shape of the molded product.
[0030]
Further, the end surfaces of the first and second sprue bushings 21 and 31 are opposed to each other, and the first sprue bushing 21 is advanced by the first hydraulic piston 26 at the time of injection. The first sprue bushing 21 is driven. The driving mechanism to be performed is not limited to the above embodiment.
Further, the drive mechanism for driving the internal pressure removing pin 37 and the second valve pin 38 forward and backward is not limited to the above embodiment.
[0031]
【The invention's effect】
Since the present invention is configured as described above, it has the following effects.
a. Molded products with different shapes can be molded simultaneously with one mold, productivity can be improved, and the number of molds can be halved, thereby greatly reducing the cost of the molded products.
b. By causing the end surfaces of the divided sprue bushings to abut and increasing the surface pressure during injection, resin leakage from the divided surface can be prevented.
c. By reducing the internal pressure of the sprue bush after injection, resin leakage from the open gate can be prevented.
[Brief description of the drawings]
FIG. 1 is a longitudinal side view of an injection mold showing a first embodiment of the present invention.
FIG. 2 is a plan view of the injection mold according to the embodiment.
3 is a cross-sectional view taken along the line AA in FIG.
4 is a cross-sectional view taken along line BB in FIG.
FIG. 5 is an operation explanatory view of the injection mold according to the embodiment.
FIG. 6 is an explanatory diagram of the operation of the injection mold according to the embodiment.
[Explanation of symbols]
2 ... fixed mold, 3 ... movable mold, 4 ... split mold, 8 ... first cavity, 11 ... second cavity, 14 ... resin passage , 15 ... first gate, 17 ... gate pin, 20 ... split Surface 21, first sprue bushing 22, first valve pin 24, first drive mechanism 31, second sprue bushing 35, open gate 37, internal pressure removal pin 38, second valve pin 40 ... Second drive mechanism

Claims (3)

A fixed mold 2, a movable mold 3 that can be brought into and out of contact with the fixed mold 2, and a fixed mold 2 provided between the fixed mold 2 and the movable mold 3. The split mold 4 is divided in the lateral direction as it is retreated, and the first and second molds have different shapes between the fixed mold 2 and the split mold 4 and between the fixed mold 2 and the movable mold 3 . 1 is an injection mold in which one cavity 8 and a second cavity 11 are provided, and a molded product having a different shape is simultaneously molded with one mold,
The fixed mold 2 has a resin injection port, a resin passage 14 communicating with the resin injection port, a first gate 15 communicating with the resin passage 14 and guiding the molten resin to the first cavity 8, and a gate pin 17 for opening and closing the first gate 15, open to the dividing plane 20 of the split molds 4 of the fixed die 2 and the molten resin communicating with the resin passage 14 to guide the second cavity 11 and the first sprue bushing 21 freely advance and retreat in the axial direction, are interpolated to the first sprue bushing 21, and a second freely advance and retreat in the axial direction 1 of the valve pin 22, the first sprue bushing during injection And a first drive mechanism 24 for advancing 21 in the split mold 4 direction and retracting the first valve pin 22 to open the gate 23 of the first sprue bush 21.
The split mold 4 has a second sprue bush 31 having a gate 32 facing the first sprue bush 21, and an open communicating with the second sprue bush 31 to guide the molten resin to the second cavity 11. A gate 35, an internal pressure removing pin 37 inserted in the second sprue bush 31 so as to be movable back and forth in the axial direction, a second valve pin 38 for opening and closing the gate 32, and a second valve pin 38 after injection. An injection mold comprising a second drive mechanism for moving forward to close the gate 32 and retracting the internal pressure removing pin 37 to remove the internal pressure of the second sprue bushing 31.   The first drive mechanism 24 includes a first hydraulic cylinder 25 provided in the fixed mold 2 and a first hydraulic cylinder 25 provided in the first hydraulic cylinder 25 for driving the first sprue bush 21. A piston 26, a second hydraulic cylinder 27 provided in the first piston 26, and a second piston 28 provided in the second hydraulic cylinder 27 and driving the first valve pin 22 are configured. The injection mold according to claim 1, wherein the injection mold is performed. The second drive mechanism 40 includes a moving block 41 freely advance and retreat in a direction perpendicular to the moving direction of the pressure removal pin 37 provided in the split molds 4, forward and backward of the moving block 41 is provided on the moving block 41 2. An injection mold according to claim 1, comprising a cam groove that opens and closes the second valve pin by movement to open and close the gate and an inclined surface 43 that advances and retracts the internal pressure removing pin.

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