JPH11105091A - Injection molding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To cool a core member sufficiently within a prescribed period by a method in which a driving means is arranged in a core mold member, the core member is cooled by a cooling means corresponding to the action of a molding mold. SOLUTION: A gear 36, accompanied by a core member 34, rotates at a prescribed angle and in the normal direction, and the male screw part of the member 34 enters a cavity 26c. After a molten material being packed in the cavity 26c at a prescribed pressure, the material is cooled. After the elapse of a prescribed length of time from the packing of a molding material, a hydraulic pressure control circuit supplies a prescribed actuation hydraulic pressure to an actuator on the basis of a control signal exhibiting a mold opening starting state from a control part. The gear 36, accompanied by the core member 34, rotates at a prescribed angle in the reverse direction, the male screw part of the member 34 is retracted from the cavity 26c. Since the male screw part is cooled to a prescribed temperature or below, a molding is protected from damage in demolding.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an injection molding apparatus for injecting a molten molding material into a mold cavity to obtain a molded product.

[0002]

2. Description of the Related Art In an injection molding apparatus, in general, when molding conditions, for example, temperature of a mold are not properly controlled, it causes dimensional defects of a molded product obtained or breakage of the molded product at the time of mold release. In some cases, the temperature of the mold is strictly controlled by controlling the temperature of cooling water in a cooling water circulation device provided inside the mold and indirectly cooling the mold.

[0003] In a molded product molded by an injection molding apparatus, for example, in a mold provided with a cavity in which a molded product in which a female screw portion is integrally molded is provided, the mold advances and retreats into the cavity. A core member forming a female screw portion is provided around the cavity. A male screw portion is formed at a portion of the outer peripheral portion of the core member that enters the cavity, corresponding to the female screw portion.

[0004]

When the core member is cooled as described above, the temperature of the mold is lowered and the mold is indirectly cooled. However, the mold enters the cavity during molding. When the external thread of the core member, which is relatively hot, is cooled indirectly by reducing the temperature of the mold,
The male screw portion is not sufficiently cooled within a predetermined period, and there is a possibility that the molded product may be damaged at the time of release.

In view of the above problems, the present invention relates to an injection molding apparatus for obtaining a molded product by injecting a molten molding material into a mold cavity, wherein the core member is sufficiently cooled within a predetermined period. It is an object of the present invention to provide an injection molding apparatus capable of performing the following.

[0006]

In order to achieve the above-mentioned object, an injection molding apparatus according to the present invention provides a molded article main body in a mold having a cavity into which a molded material is injected to form a molded article main body. A core mold member which advances and retreats with respect to the cavity portion to form a concave portion forming a part of the core member, a cooling means arranged on the core mold member for performing an operation of cooling the core mold member, and And a driving means for performing an operation of cooling in response to the request.

[0007]

FIG. 1 schematically shows a main part of an example of an injection molding apparatus according to the present invention.

A molded product obtained by the apparatus shown in FIG. 1 is, for example, a camera body case 10 which forms a part of an outer shell of a camera as shown in FIG.

The camera body case 10 includes a film sending section 11 for maintaining the photosensitive layer of the film sequentially fed from the loaded film container at a predetermined position with respect to the optical system.
B and a film winding unit 11A that winds the film from the film sending unit 11B.

The film feeding section 11B has a substantially rectangular parallelepiped shape having a curved portion at one end, and has a concave portion 12B inside the curved portion. One flat portion 10F connected to the concave portion 12B of the film sending portion 11B is provided with two strip-shaped projections 10f extending in parallel with each other, and an opening 10c is provided between the projections 10f. On one side of the protrusion 10f, grooves 10a and 10b are provided in a row in parallel with the protrusion 10f. Further, a female screw hole 14 having a predetermined depth is integrally formed and provided on one side surface of both side surfaces connected to both end portions of the flat portion 10F of the film sending portion 11B. For example, a male screw for attaching a tripod of the camera body is screwed into the female screw hole 14.

The film winding section 11A connected to the other end of the film sending section 11B is formed so as to extend along the width direction from the other end of the film sending section 11B. Further, the film winding portion 11A has a curved portion protruding in the thickness direction. A concave portion 12A is formed inside the curved portion.

The apparatus shown in FIG. 1 has a fixed support plate 16 fixed to four tie bars 28 (only one of which is shown in FIG. 1) inserted into the through hole, and a fixed support plate 16. Tie bar 28 which is arranged opposite to and inserted into the through hole
The movable supporting plate 22 slidably supported by the fixed mold 16 fixed between the fixed supporting plate 16 and the movable supporting plate 22
8. The movable mold 24 and the movable support plate 22 are connected to the movable mold 2
4 together with a mold clamping cylinder portion 42 which presses or separates the fixed mold 18 and the fixed support plate 16 from each other.

The fixed support plate 16 has an injection portion 16s at a substantially central portion to which an injection nozzle of an injection device (not shown) is connected.

The fixed-side mold 18 has one end face supported by the fixed support plate 16 and includes a mold 20. At a substantially central portion of the fixed mold 18, there is provided a spool 18 s for guiding the molten molding material supplied to a position corresponding to the injection portion 16 s of the fixed support plate 16 into the mold 20.

One end of the spool 18s is
Runner 26 formed over a metal mold 26 to be described later.
r. The runner 26r communicates with a cavity 26c formed in the mold 26 via a gate 26g.

The movable mold 24 has one end face supported by the movable support plate 22 and includes a mold 26. The movable mold 24 is connected to the movable support plate 22 by a connection mechanism (not shown) together with the mold 26, and the movable support plate 2 is
By moving 2, a close state or a separated state is taken with respect to the separation surface between the fixed side mold 18.

As shown in FIG. 1 and FIG. 2, a female screw hole 24 a having one end opening into a cavity 26 c of the mold 26 is formed in the movable mold 24.
It is provided so as to be orthogonal to the inner wall surface forming 6c.

As shown in FIG. 2, the female screw hole 24a of the camera body case 10, which is a molded product, is formed in the female screw hole 24a.
4 are rotatably fitted to each other. A portion of the outer periphery of one end of the core member 34 that is fitted into the female screw hole 24a has a male screw portion 34s.
Has a predetermined length. The male screw portion 34 has an outer diameter and a pitch corresponding to the female screw hole 14 of the camera body case 10 which is a molded product. A gear 36 is provided at the other end of the core member 34, for example, so as to be spline-fitted, slidable in the axial direction, and engaged in the circumferential direction.

The gear 36 is engaged with an actuator 30 fixed to the movable mold 24, for example, a pinion gear 32 fixed to an output shaft of a hydraulic motor. The module of the gear 36 is made larger than the module of the pinion gear 32. The actuator 30 is activated by a hydraulic pressure supplied from a hydraulic control circuit (not shown), and its output shaft is rotated in the forward or reverse direction.

Accordingly, when the gear 36 is rotated in the reverse direction or the forward direction, the external thread portion 34s of the core member 34
Enters the cavity 26c or the cavity 26c
You will be retreated from within.

The core member 34 has a cooling pipe 40 therein as a cooling means along the central axis thereof. One end of the cooling pipe 40 reaches the end of the male thread portion 34, and the other end of the cooling pipe 40 projects a predetermined length from the end of the core member 34.

At the protruding other end of the cooling pipe 40, four disc-shaped cooling fins 38a as heat radiating portions 38 are provided, each having a flat surface orthogonal to the axis of the cooling pipe 40 and a predetermined length. Are arranged parallel to each other along the axial direction with an interval of. This allows
After the male screw portion 34s of the core member 34 is set to a relatively high temperature state, the heat conducted through the cooling pipe 40 is radiated to the atmosphere via the heat radiating portion 38 to cool the male screw portion 34s of the core member 34. Becomes

The heat dissipating portion 38 is not limited to this example. For example, as shown in FIG. 4, four rectangular cooling fins 46a as heat dissipating portions 46 are radially provided from the end of the core member 34 at predetermined positions. May be provided at the other end of the cooling pipe 44 which protrudes by a length. In FIG. 4 or in another example described later, FIG.
In the example shown in FIG. 1, the same components are denoted by the same reference numerals, and the description thereof will not be repeated.

In FIG. 4, each cooling fin 46
a has one of its long sides fixed to the other end of the cooling pipe 44 so as to cross each other at a right angle. Since the cooling fin 46a is fixed to the other end of the cooling pipe 44 in this manner, when the cooling pipe 44 is rotated with the cooling fin 46a, heat is efficiently radiated to the atmosphere.

With this configuration, the movable-side support plate 22 is moved together with the movable-side mold 24 toward the fixed-side mold 18 by the mold clamping cylinder 42, as shown by the two-dot chain line in FIG. After the mold is closed at a predetermined pressure, a hydraulic control circuit supplies a predetermined operating oil pressure to the actuator 30 based on a control signal indicating a completion state of the mold closing from a control unit (not shown). As a result, the gear 36 is rotated in the forward direction by a predetermined angle with the core member 34,
The externally threaded portion 34s of the core member 34 is inserted into the cavity 26c.

Next, the molten molding material is supplied to the cavity 2.
After filling into 6c at a predetermined pressure, the molding material is cooled. At this time, the temperature of the male screw portion 34s of the core member 34 that has entered the cavity 26c is efficiently radiated by the heat radiating portion 38 and lowered with a decrease in the temperature of the molding material.

Subsequently, after the molding material is filled into the cavity 26c at a predetermined pressure, after a predetermined time has elapsed, the hydraulic control circuit adjusts a predetermined operating oil pressure based on a control signal indicating a mold opening start state from the control unit. It is supplied to the actuator 30. Thus, the gear 36 is rotated in the opposite direction by a predetermined angle with the core member 34, and the external thread portion 34s of the core member 34 is retracted from the inside of the cavity 26c.

Accordingly, the external thread portion 34s of the core member 34
Is sufficiently cooled to a temperature equal to or lower than a predetermined temperature, so that breakage of the molded article at the time of mold release can be avoided.

Then, the movable-side support plate 22 is moved together with the movable-side mold 24 by the mold clamping cylinder 42 to the fixed-side mold 18.
The molded product is protruded from the cavity 26c by a protruding mechanism (not shown).

FIG. 5 shows a main part of another example of the injection molding apparatus according to the present invention.

In FIG. 5, in the example shown in FIG. 2, the heat of the core member 34 is radiated to the outside through the cooling pipe 40 and the heat radiating portion 38, so that the core member 34 is cooled.
Temperature was lowered efficiently, but instead,
The core member 52 is located at a position facing the cavity 48c of the movable mold 48 and corresponding to the female screw hole 14 of the molded product.
Is provided, a cooling water circulation passage 50 for circulating a predetermined amount of cooling water Wa for indirectly cooling the core member 50 is provided so as to surround the vicinity of the portion where the core member 52 is disposed. . The other components except the movable mold 48 are the same as those in the example shown in FIG.

In FIG. 5, the core member 5 is located at a position facing the cavity 48 c of the movable mold 48 and corresponding to the female screw hole 14 of the camera body case 10.
A female screw hole 48a into which the two male screw portions 52s are fitted is provided. Around the vicinity of the female screw hole 48a, cooling water Wa of a predetermined temperature is surrounded so as to surround the female screw hole 48a.
Water circulation passage 5 for circulating water in the direction indicated by the arrow in FIG.
0 is provided. The cooling water circulation passage 50 is provided with a circulation pump Pu. The circulation pump Pu is driven and controlled by the control unit based on a control signal indicating a mold opening start state, and is brought into an operating state, and is stopped after a predetermined period has elapsed.

A rotating shaft 54 to which a gear 56 meshing with the pinion gear 32 is fixed is connected to one end of the core member 52 so as to be relatively movable on the same axis along the axial direction. When the actuator 30 is activated by a hydraulic pressure supplied from a hydraulic control circuit (not shown) and its output shaft is rotated in the forward or reverse direction, the gear 56 is rotated in the reverse or forward direction. The male screw portion 52s of the core member 52 has the cavity 48c.
Of the cavity 48c.

With this configuration, in the mold closed state, after the molding material is filled into the cavity 48c at a predetermined pressure, and after a predetermined time has elapsed, the control unit circulates based on a control signal indicating a mold opening start state. By controlling the driving of the pump Pu, the cooling water Wa is circulated in the cooling water circulation passage 50, and the hydraulic control circuit supplies a predetermined operating oil pressure to the actuator 30.

As a result, the gear 56 is rotated in the opposite direction by a predetermined angle with the rotation shaft 54 and the core member 52,
The external thread portion 52s of the core member 52 is retracted from the inside of the cavity 48c while being indirectly cooled by the cooling water Wa.

Accordingly, the external thread portion 52s of the core member 52
Is sufficiently cooled to a temperature equal to or lower than a predetermined temperature, so that breakage of the molded article at the time of mold release can be avoided.

FIG. 6 shows still another example of the injection molding apparatus according to the present invention.

In FIG. 6, in the example shown in FIG.
Actuator 3 as means for rotating core member 34
0 is used, but instead, a rack 62 in which the gear 36 meshes is provided in the fixed mold 18 via a rack connecting member 60 as means for rotating the core member 34.

The rack 62 is provided so as to be substantially parallel to the tie bar 28 via a rack connecting member 60. As shown by a solid line in FIG. 6, the length of the rack 62 is determined by the distance between the rack 62 and the gear in a state where the fixed mold 18 and the movable mold 24 are separated from each other and a molded product can be taken out. 36 are sized so that they can mesh with each other.

When the movable mold 24 is moved in the direction approaching the fixed mold 18, the gear 36
The core member 34 is rotated a predetermined number of times in the counterclockwise direction when viewed from the side 8 and the tip of the core member 34 enters the cavity 26c by a predetermined amount. When the movable mold 24 is moved in a direction away from the fixed mold 18, the gear 36
The core member 34 is rotated clockwise as viewed from the side, and the core member 34 is retracted from the inside of the cavity 26c. Therefore, the core member 34
When the movable mold 24 enters the mold closed state, the male screw portion 34s enters the cavity 26c by a predetermined amount. When the movable mold 24 transitions to the mold open state, the male screw of the core member 34 The portion 34s is retracted from the inside of the cavity 26c. That is, in this example, the core member 34 can be rotated in accordance with the operation of the movable mold 24 without providing a drive source for rotating the core member 34 independently.

With this configuration, the molten molding material is supplied to the cavity 2 in the mold closed state as in the above-described example.
After filling into 6c at a predetermined pressure, the molding material is cooled. At this time, the temperature of the male screw portion 34s of the core member 34 that has entered the cavity 26c is efficiently radiated to the atmosphere through the heat radiating portion 38 as the temperature of the molding material decreases, and is reduced.

Next, after the molding material is filled into the cavity 26c at a predetermined pressure, after a predetermined time has elapsed, when the mold opening state is started, the gear 36 is rotated by a predetermined angle with the core member 34, The external thread portion 34s of the core member 34 is retracted from the inside of the cavity 26c. Therefore, since the male screw portion 34s of the core member 34 is sufficiently cooled to a predetermined temperature or lower, damage to the molded product at the time of releasing the mold is avoided.

Then, the movable-side support plate 22 is moved together with the movable-side mold 24 by the mold-clamping cylinder 42 to the fixed-side mold 18.
The molded product is protruded from the cavity 26c by a protruding mechanism (not shown).

In the example shown in FIG. 6, the core member 34 provided with the heat radiating portion 38 is used.
Without being limited to this example, for example, the core member 34 provided with the heat radiating portion 46 shown in FIG. 4 may be used.

[0045]

As is apparent from the above description, according to the injection molding apparatus of the present invention, the driving means is disposed on the core mold member and the cooling means for performing the operation of cooling the core mold member operates the cooling means. Since the cooling operation is performed according to the state, the core member can be sufficiently cooled within a predetermined period.
Therefore, in the case of opening the mold, it is possible to prevent the molded product from being damaged due to an undesired release failure.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a schematic configuration of an example of an injection molding apparatus according to the present invention.

FIG. 2 is an enlarged partial cross-sectional view showing a main part in the example shown in FIG.

FIG. 3 is a perspective view showing a molded product formed by the apparatus of the example shown in FIG. 1;

FIG. 4 is an enlarged partial cross-sectional view showing a modified example of the heat radiating unit in the example shown in FIG.

FIG. 5 is a partial sectional view schematically showing a configuration of a main part of another example of the injection molding apparatus according to the present invention.

FIG. 6 is a configuration diagram showing a schematic configuration of still another example of the injection molding apparatus according to the present invention.

[Explanation of symbols]

 Reference Signs List 10 Camera body case 14 Female screw hole 18, 20 Fixed mold 24, 26, 48 Movable mold 26c, 48c Cavity 30 Actuator 32 Pinion gear 34 Core member 34s Male thread 36 Gear 38, 46 Heat radiator 40, 44 Cooling pipe 50 Cooling water Wa circulation passage Pu circulation pump Wa Cooling water

Claims (10)

[Claims] 1. A molding die having a cavity into which a molding material is formed by injection of a molding material, a core mold member which advances and retreats with respect to the cavity to form a concave portion which forms a part of the molding product main body. A cooling unit arranged on the core mold member for performing an operation of cooling the core mold member; and a driving unit for causing the cooling unit to perform an operation of cooling according to an operation state of the molding die. An injection molding apparatus characterized by being performed. 2. The cooling means has a heat radiating portion provided with a plurality of plate-shaped members, and the driving means rotates the heat radiating portion to perform an operation of cooling the core-type member. The injection molding apparatus according to claim 1, wherein: 3. The cooling means includes a circulation passage provided so as to surround the vicinity of the core-shaped member and through which a cooling medium is circulated, and the cooling medium is circulated by the driving means, whereby the cooling medium is circulated. The injection molding apparatus according to claim 1, wherein an operation of cooling the core mold member is performed. 4. The injection molding apparatus according to claim 2, wherein the heat radiating portion is formed by arranging a plurality of plate members radially with respect to a heat conducting member provided on the core member. 5. The rack is supported by one of a plurality of relatively movable molds, and the driving means is provided on the core mold member disposed on the other mold. 3. The injection molding apparatus according to claim 2, further comprising a gear engaged with said rack. 6. The injection molding apparatus according to claim 1, wherein the core mold member has a male screw part for forming a female screw part formed in a concave part forming a part of the molded product main body part. 7. The injection molding apparatus according to claim 1, wherein said core mold member is rotated by driving force from said driving means and moves forward and backward with respect to said cavity. 8. The method according to claim 3, wherein said core mold member is provided on said molding die, and is rotated by rotating means for rotating said core mold member to advance and retract with respect to said cavity. Injection molding equipment. 9. The injection molding apparatus according to claim 3, wherein the cooling medium is a liquid. 10. The injection molding apparatus according to claim 2, wherein said driving means includes a hydraulic motor.