KR101582589B1 - Injection mold for forming product having female screw surface - Google Patents

Abstract

Disclosed is a mold for injection-molding a product having a female-screw side. The injection mold for a product having a female-screw side includes: an upper mold having an upper cavity side, which limits at least a portion of the shape of an upper side of the product; a lower mold having a lower cavity side, which limits at least a portion of the shape of a lower side of the product; and an elevation core which limits the shape of the female-screw side and is supported by the upper mold or the lower mold. The elevation core includes: a support core unit which can be elevated and moved between a first location, which is relatively closer to either the upper mold or the lower mold which is located on a side opposite to a mold supporting the elevation core and a second location which is relatively farther than the first location from the mold located on the opposite side; and a plurality of first screw tab core units and second screw tab core units which encircle a support core unit when the support core unit is located in the first location and are alternately arranged to limit the shape of the female-screw side. If the support core unit is moved from the first location to the second location after the upper mold and the lower mold are closed, the first screw tab core unit and the second screw tab core unit contract toward the inside and then are separated from the female-screw side of the product. If the upper mold and the lower mold are opened, the elevation core is moved outside the product.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an injection mold for a product having a female-

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection mold, and more particularly, to an injection mold for forming a product having a female thread.

Injection molding is a method in which a molten resin is injected into a mold and cooled to form a product. Compared with other molding methods such as compression molding and extrusion molding, And the size is limited, and productivity and workability are excellent, and it is widely used for molding of plastic products.

For example, a product such as a container or a cap for receiving a liquid has products with female threads. Such a female screw surface serves as an undercut preventing injection of the product in injection molding of the product. In other words, a product having an undercut can not be taken out by simply separating the upper mold and the lower mold which are in close contact with each other, and a more complicated mechanism is required.

FIG. 1 is a perspective view showing an example of a product having a female screw surface. Referring to FIG. 1, the illustrated product 1 is an upper portion of a cooling water tank of an automobile, And a female screw surface 4 is formed on the inner peripheral surface of the opening 3 of the spout 2. It is possible to close the opening 3 of the spout 2 with a cap formed with a male or female slope.

The female screw surface 4 forms an undercut. In the prior art, a screw tap is formed at the distal end portion. A screw tap shaft, which moves up and down according to rotation in the clockwise and counterclockwise directions, A method in which the product 1 is taken out by separating the upper mold and the lower mold is applied. However, in such a method, it takes a long time to rotate the threaded tap screw shaft in the opposite direction after the screw tap shaft is rotated in one direction before injection of the molten resin and after the resin injection and curing, Is lowered.

Korean Patent Publication No. 10-1321748

The present invention provides a mold for injection molding a product having a female thread surface, and an injection mold having improved productivity.

According to a preferred embodiment of the present invention, there is provided an injection-molded metal mold for a product having a female screw surface, the inner undercut structure including a female screw surface as well as an outer undercut structure.

The present invention relates to a mold for injection molding an article having a female thread surface, comprising: an upper mold having an upper cavity surface defining at least a part of an upper side surface shape of the article; A lower mold having a lower cavity surface and an elevating core which defines a shape of the female screw and is supported by the upper mold or the lower mold, A support core portion that is movable up and down between a first position relatively close to a mold positioned opposite to the supported mold and a second position relatively far from the mold positioned opposite to the first position, Wherein when the support is in the first position, the outer circumferential surface of the support core portion is surrounded and alternately arranged, Wherein when the support core moves from the first position to the second position in a state that the upper mold and the lower mold are closed, The plurality of first and second screw tap cores shrink inward and are separated from the female screw surface of the product, and when the upper mold and the lower mold are opened, the lifting core moves to the outside of the product , And an injection molding die for a product having a female screw surface.

When the support core part moves from the first position to the second position, the plurality of second screw-tab core parts can move more inward than the plurality of first screw-tab core parts.

The number of the first screw core portions and the number of the second screw core portions may each be three.

The support core portion may have a plurality of inclined side surfaces, and the plurality of first screw tap core portions and the plurality of second screw tap core portions may be slidably coupled to the plurality of inclined side surfaces.

The elevating core may be supported by the upper mold.

The elevating core may further include a distal core part provided at a distal end of the elevating core to closely contact the lower cavity surface when the upper mold and the lower mold are closed.

According to the present invention, an injection mold of an article having a female thread surface is provided with a power for elevating and lowering the support core portion between the first position and the second position, comprising an actuator including a motor or a hydraulic cylinder, ).

The injection molding die of the product having the female thread surface according to the present invention is characterized in that when the upper mold and the lower mold are closed, the outer shape of the spout And a plurality of slide cores moving to define a plurality of slide cores.

At least one slide core of the plurality of slide cores is supported by the upper mold and the slide core supported by the upper mold is brought into contact with the lower mold as the upper mold and the lower mold approach each other, The slide core moving toward the position defining the shape of the outer periphery of the spigot while closely contacting the lower mold when the mold is closer to the lower mold and the slide core being supported by the upper mold when the upper mold and the lower mold are closed, The slide core supported by the upper mold may be provided with a hook so as to maintain a state of being in tight contact with the lower mold, and the lower mold may include a hook fastener fastened to the hook.

The injection molding die of the present invention can avoid the undercut where the female screw is formed by raising and lowering the elevating core formed with the male screw tab without rotating the screw tap shaft while rotating the screw tap shaft. Therefore, the cycle including the mold closing and mold opening of the injection molding metal mold can be shortened and the productivity of the product can be improved.

The injection molding die of the present invention further includes not only an elevating core having a male threaded tapped tab but also a plurality of sliding cores moving horizontally in association with the opening and closing of the metal mold to form an internal undercut structure, A product having an undercut structure together with a complicated shape can be injection-molded.

Fig. 1 is a perspective view showing an example of a product having a female type thread surface.
2 is a perspective view showing a state in which an injection molding die of a product having a female thread surface is closed according to an embodiment of the present invention.
FIGS. 3 and 4 are perspective views illustrating the lower side of the upper mold of FIG. 2 and the upper side of the lower mold of FIG. 2;
5 and 6 are perspective views showing the upper side of the lower mold of Fig. 2, the screw tab lifting core, and the first to third slide cores together, Fig. 5 is a view showing a state where the upper mold and the lower mold are opened And Fig. 6 is a view showing a state in which the upper mold and the lower mold are closed.
Figs. 7 and 8 are exploded perspective views showing the screw tab lifting cores of Figs. 5 and 6, wherein Fig. 7 is a top view and Fig. 8 is a bottom view.
9 to 12 are front views sequentially showing the operation of the screw tab lifting core.
Figs. 13 to 15 are perspective views showing the first to third slide cores of Figs. 5 and 6, respectively.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an injection molding die of a product having a female thread surface according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. The terminology used herein is a term used to properly express the preferred embodiment of the present invention, which may vary depending on the intention of the user or operator or the custom of the field to which the present invention belongs. Therefore, the definitions of these terms should be based on the contents throughout this specification.

Fig. 2 is a perspective view showing a state in which an injection-molding mold of a product having female threads is closed, according to an embodiment of the present invention, Figs. 3 and 4 are sectional views of the lower side of the upper mold of Fig. 5 and 6 are perspective views showing the upper side of the lower mold of Fig. 2, the screw tab lifting core, and the first to third slide cores together, Fig. 5 is a perspective view of the upper FIG. 6 is a view showing a state in which the upper mold and the lower mold are closed. FIG.

2 to 4, an injection molding die 10 of a product having a female thread surface according to an embodiment of the present invention specifically includes an upper portion 1 of a cooling water tank as shown in Fig. 1 The upper mold 11, the lower mold 60, the lifting core 20 and the first to third slide cores 81, 100, and 115 are provided.

The upper mold 11 includes an upper base 12, an upper circular plate 14 supported by the upper base 12, and an upper core 16 supported by the upper circular plate 14. The upper core 16 is fixedly supported on the upper circular plate 14 and includes a first upper cavity surface 17 and a second upper cavity surface 18 defining a portion of the upper side profile of the product 1 ). The lower mold 60 includes a lower base 61, a lower circular plate 63 supported by the lower base 61, and a lower core 65 supported by the lower circular plate 63. The lower core 65 is fixedly supported on the lower original plate 63 and has a lower cavity surface 67 which defines the lower side shape of the product 1. [

The upper mold 11 is fixedly fixed and the lower mold 60 moves toward the upper mold 11 or moves away from the upper mold 11 in parallel with the Z axis so that the upper mold 11 11 or spaced apart from the upper mold 11. As shown in FIG. However, contrary to the above, the upper mold 11 may be a movable side mold and the lower mold 60 may be a fixed side mold.

The elevating core 20 defines the shape of the female screw surface 4 (see FIG. 1) formed on the inner peripheral surface of the spout 2 (see FIG. 1) of the product 1 and is supported by the upper metal mold 14 And male screw taps 31 and 37 are formed at the lower end. The first slide core 81 has a first upper shape defining surface 82 defining a part of the upper side shape of the product 1 and is slidably supported on the lower original plate 63. The second and third slide cores 100 and 115 are provided with second and third upper shape defining surfaces 101 and 116 respectively defining a part of the top surface shape of the product 1, As shown in Fig.

The product 1 is provided with a spout 2 (see Fig. 1) on the upper side of which the female thread 4 is formed on the inner side and the connection between the semicircular body 5 of the product 1 and the spout 2 The portion 6 (see FIG. 1) is formed to have a narrow diameter to form an outer undercut which makes it difficult to take out the article 1 to be injection-molded. When the upper mold 11 and the lower mold 60 are closed, the first to third slide cores 81, 100, and 115 move to the center of the lower cavity surface 67, ). To this end, the first to third snout-shaped limiting surfaces 86, 102, 120 are provided on each of the first to third slide cores 81, 100, 115, and the first to third snout- 103, and 121 protruding further toward the center of the lower cavity surface 67 are formed on the lower side of the upper cavity surface 102, 120 to define the shape of the outer undercut.

When the upper mold 11 and the lower mold 60 are closed, the first and second upper cavity surfaces 17 and 18, the first to third upper shape defining surfaces 82, 101 and 116, And the cavities through which the molten resin is injected and injected by the second screw tabs 31 and 37 and the lower cavity surface 67 are limited. In particular, the first to third spout-shaped defining surfaces 86, 102, The outer shape of the spout 2 is limited by the first and second screw tabs 31 and 37 and the shape of the female screw 4 is limited by the first and second screw taps 31 and 37. [

On the other hand, the semicircular body 5 of the product 1 is provided with a long projection 7 (see Fig. 1) horizontally extending in the form of a tube and a pair of short projections The first slide core 81 has a first upper shape defining surface 82 formed with a long protrusion forming groove 82 extending in the horizontal direction corresponding to the long protrusion 7, And a through-hole forming pin 84 (see FIG. 13) extending in the horizontal direction so as to correspond to the through hole formed in the longitudinal direction of the elongate projection 7. The third slide core 115 has a pair of short protrusion forming grooves 117 and 118 formed in the third upper side shape defining surface 116 in a horizontal direction corresponding to the pair of short protrusions 8a and 8b (See Fig. 15).

7 and 8 are exploded perspective views showing the screw tab lifting cores of FIGS. 5 and 6, wherein FIG. 7 is a top view, FIG. 8 is a bottom view, In order from the top. 7 and 8 together, the lifting core 20 includes a supporting core portion 21, three first screw thread core portions 30, three second screw thread core portions 36, (43), and an elevation guide pin (47).

The support core portion 21 has a first position (see FIG. 9) relatively closer to the lower mold 60 (see FIG. 2) and a second position 10) in parallel with the Z-axis. An actuator 51 fixedly supported on the upper mold 11 provides power for moving the support core portion 21 between the first and second positions. The actuator 51 may include an electric motor or a hydraulic cylinder. For example, the supporting core portion 21 and the lifting plate (not shown) are fixedly connected by a plurality of supporting core portion fastening bolts 49, and the actuator 51 lifts and drives the lifting plate, (21) can ascend and descend. The elevation guide pin 47 extends parallel to the Z axis and passes through the supporting core portion 21 to guide the elevation between the first position and the second position of the supporting core portion 21. [

The three first screw threaded core portions 30 and the three second screw threaded core portions 36 are arranged alternately surrounding the outer peripheral surface of the support core portion 21. [ A first screw tab 31 is formed at the lower end of the three first screw core tapes 30 and a second screw tab 37 is formed at the lower end of the three second screw core tapes 36. The three first screw tabs 31 and the three second screw tabs 37 alternately arranged when the support core portion 21 is in the first position are combined to form the female threaded portion 4 of the product 1 1) is limited.

The supporting core portion 21 has three first inclined side surfaces 24 to which the inner side surfaces of the first screw tap core portion 30 are contactably supported and an inner side surface of the second screw tap core portion 36 And has three second inclined side surfaces 26. [ A first guide rail projection 25 extending in the longitudinal direction of the inclined side surface 24 is formed in the first inclined side surface 24 and a second guide rail projection 25 is formed in the inner side surface of the first screw tap core portion 30, A first guide groove 33 in which the projection 25 is received is formed so that the first screw thread core portion 30 is slidably engaged with the first inclined side surface 24. A second guide rail projection 27 extending in the longitudinal direction of the inclined side surface 26 is formed on the second inclined side surface 26 and a second guide rail projection 27 is formed on the inner side surface of the second screw tap core portion 36, A second guide groove 39 in which the guide rail projection 27 is received is formed and the second screw threaded core portion 36 is slidably engaged with the second inclined side surface 26.

When the support core portion 21 moves from the first position to the second position, the first screw-tab core portion 30 and the second screw-tab core portion 36 are lifted so as not to rise together with the support core portion 21 Is limited. Thus, the three first screw thread core portions 30 and the three second screw thread core portions 36 move inward toward the elevation guide pin 47. 1) formed by curing the molten resin injected into the cavity (not shown) defining the shape of the product 1 (see Fig. 1) (30) and the second threaded tab core portion (36) are separated.

Specifically, when the size of the first screw-tab core portion 30 is larger than the size of the second screw-tab core portion 36 and the support core portion 21 moves from the first position to the second position, The screw tab core portion 36 moves more inward toward the elevation guide pin 47 than the three first screw tab core portions 30 so that the lower ends of the three second screw core portions 36 Respectively. At this time, the lower end inner edge 40 of the three second screw threaded core portions 36 is formed into a triangular arc shape so that the elevation guide pin 47 can pass therethrough, and the lower inner peripheral edge 40 Are formed to be in contact with each other, an opening having an inner diameter larger than the diameter of the lifting guide pin 47 is formed.

On the other hand, the distal core portion 43 is fixedly fastened to the lower end of the elevation guide pin 47 by the fastening bolt 45. The distal core portion 43 is seated on the end corner seating surface 69 (see FIG. 4) at the center of the lower cavity surface 67 (see FIG. 4) when the upper mold 11 and the lower mold 60 are closed .

Hereinafter, the operation of the lifting core 20 will be described with reference to Figs. 9 to 12 sequentially. 9, the upper mold 11 (see FIG. 2) and the lower mold 60 (see FIG. 2) are closed and the supporting core portion 21 of the lifting core 20 And is located at the first position. At this time, the three first threaded tap core portions 30 and the three second threaded tap core portions 36 are moved radially outward about the elevation guide pin 47, And three second screw tabs 37 are alternately connected to define the shape of the female screw 4. In this state, the molten resin is injected into the cavity and hardened to form the product 1 (see Fig. 1), and a plurality of first and second screw tabs 31 and 37, in which the female screw surfaces 4 are alternately arranged, .

Next, as shown in Fig. 10, when the support core portion 21 is raised to the second position by the power of the actuator 51 (see Fig. 2), the three first screw thread core portions 30 and the three second screw tab core portions 36 move inward toward the elevation guide pin 47 so that the first and second screw tabs 31, Separated.

Next, when the upper mold 11 and the lower mold 60 are opened, as shown in FIG. 11, the lower mold 60 is moved in parallel with the direction of the Z axis negative (-) with respect to the lifting core 20 The lifting core 20 moves to the outside of the spout 2. In this state, the product 1 is attached to the lower cavity surface 67 (see FIG. 4). However, the product 1 is attached to the ejection pin (not shown) almost simultaneously with the mold of the upper mold 11 and the lower mold 60 And is separated and taken out from the lower cavity surface (67).

12, the supporting core portion 21 is lowered to the first position by the power of the actuator 51 in a state where the upper mold 11 and the lower mold 60 are opened. When the upper mold 11 and the lower mold 60 are again closed, and the molten resin is injected into the cavity thus formed and hardened, the state of FIG. 9 is repeated.

Figs. 13 to 15 are perspective views showing the first to third slide cores of Figs. 5 and 6, respectively. 3, 4, and 13, the first slide core 81 is mounted on the slide core guide rail 92 provided on the lower disk 63 so as to be linearly movable on a plane parallel to the XY plane . The stopper block 94 at the rear end of the slide core guide rail 92 restricts the retreat range of the first slide core 81.

The upper circular plate 14 is provided with a driving pin 55 extending downward and an inclined hole 91 through which the driving pin 55 is inserted is provided at the rear of the first slide core 81. When the upper mold 11 and the lower mold 60 are brought close to each other in the mold closing direction, the driving pin 55 is inserted into the inclined through hole 91, The slide core 81 moves along the slide core guide rail 92 toward the center of the lower cavity surface 67. 6, when the upper mold 11 and the lower mold 60 are closed to completely close the upper core 16 and the lower core 65, the first slide core 81 is rotated in the second and third And are in close contact with the slide cores 100 and 115. At this time, the pressurized slant face 53 provided at the upper end of the drive pin 55 presses the pressurized slant face 90 provided on the first slide core 81 to firmly fix the first slide core 81 at the position.

On the other hand, when the upper mold 11 and the lower mold 60 move away from each other in the mold-closed state, the pressurized slant face 53 is separated from the pressurized slant face 90, and the drive pin 55 and the oblique holes 91 The first slide core 81 is retracted to the rear of the slide core guide rail 92. As a result,

Referring to FIGS. 3 to 6 and FIGS. 14 and 15 together, the second and third slide cores 100 and 115 are supported by the upper disk 14. Specifically, a pair of first guide sidewalls 111 is fixed to the lower side of the upper disk 14, and a second slide core 100 is supported on the pair of first guide sidewalls 111 so as to be able to move up and down . A pair of second guide sidewalls 128 are fixed to the lower side of the upper disk 14 and a third slide core 115 is supported on the pair of second guide sidewalls 128 to be movable up and down.

On both sides of the second and third slide cores 100 and 115 are formed oblique guide grooves 105 and 123 extending obliquely up and down respectively and the first and second guide side walls 111 and 128 Are inclined guide rails (112, 129) extending in the vertical direction so as to be fitted to the inclined guide grooves (105, 123), respectively. Due to such a structure, when the upper mold 11 and the lower mold 60 are brought close to each other in the mold closing direction, the pair of first guide ribs 111 are guided by a pair of first guide ribs The second slide core 100 is brought into contact with the lower circular plate 63 and the pair of second guide ribs 128 are brought into contact with the pair of second guide ribs 63 formed on the lower circular plate 63. [ And the third slide core 115 is brought into contact with the lower disk 63.

When the upper mold 11 and the lower mold 60 are further brought closer to each other, the first and second slide cores 100 and 115 are moved by the interference between the inclined guide grooves 105 and 123 and the inclined guide rails 112 and 129 The upper mold 11 and the lower mold 60 are moved to the center of the lower cavity surface 67 on the upper surface of the lower original plate 63 to mold the upper mold 16 and the lower mold 60, The first, second, and third slide cores 81, 100, and 115 are in close contact with each other and are connected to the first and second upper cavity surfaces 17 and 18 as well, The shape of the outer circumferential surface of the entire product 1 (see Fig. 1) including the backsheet 2 (see Fig. 1) is limited.

The spring damper 109 and 127 of the second and third slide cores 100 and 115 are formed in such a manner that the second and third slide cores 100 and 115 are moved in the guide sidewalls 111 and 128 from the lower mold 60 so as to relax the shock when the second and third slide cores 100, 115 collide with the lower disk 63.

The second and third slide cores 100 and 115 are provided with hooks 107 and 125 on the lower side and the first and second guide ribs 111 and 128 are formed on the side surface of the lower circular plate 63, Hook insertion grooves 74 and 79 for receiving the hooks 107 and 125 when the hooks 107 and 125 are seated in the first and second guide wall mounting grooves 71 and 76, Fastening jaws 73 and 76 are provided. When the upper mold 11 and the lower mold 60 move in the direction of being closed by the above structure, the hooks 107 and 125 are received in the hook insertion grooves 74 and 79, (100, 115) and fastened to the hook fastening tines (73, 76). Therefore, when the upper mold 11 and the lower mold 60 are closed, the second and third slide cores 100 and 115 supported by the upper circular plate 14 are firmly in contact with the lower circular plate 63 maintain.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the scope of the present invention. Therefore, the true scope of protection of the present invention should be defined only by the appended claims.

1: Product 2: Spout
4: female type abrasion surface 10: injection molding die
11: Upper mold 16: Upper core
20: lifting core 21: supporting core part
30: first screw thread core portion 36: second screw thread core portion
60: lower mold 65: lower core
67: lower cavity surface 81: first slide core
100: second slide core 115: third slide core

Claims (9)

delete 1. A mold for injection molding a product having a female-
An upper mold having an upper cavity surface defining at least a portion of an upper side profile of the article; A lower mold having a lower cavity surface defining at least a portion of a lower side profile of the article; And a lifting core supported on the upper mold or the lower mold to define a shape of the female screw surface,
Wherein the lifting core includes a first position relatively closer to a metal mold located opposite to a metal mold supported by the upper mold and a lower mold and a second position relatively away from the metal mold positioned on the opposite side from the first position, A support core portion which is movable up and down between the support cores; And a plurality of first and second screw threaded core portions surrounding the outer circumferential surface of the support core portion when the support core portion is at the first position and alternately arranged to define a shape of the female screw surface,
Wherein the support core portion includes a plurality of first inclined side surfaces to which the plurality of first screw tap core portions are slidably engaged and a plurality of second inclined side surfaces to which the plurality of second screw tap core portions are slidably engaged,
As the support core portion is moved from the first position to the second position, the first and second screw tap core portions are arranged to move inward at the same position as the female screw surface,
When the support core portion moves from the first position to the second position because the inclination of the second inclined side face is higher than the inclination of the first inclined side face so that the plurality of second screw- Wherein the core part is moved more inward than the core part. 3. The method of claim 2,
Wherein the number of the first screw core portions and the number of the second screw core portions are three, respectively. delete 3. The method of claim 2,
Wherein the lifting core is supported by the upper mold. ≪ RTI ID = 0.0 > 11. < / RTI > 6. The method of claim 5,
Wherein the elevating core further comprises a distal core portion provided at a distal end of the elevating core and closely contacting the lower cavity surface when the upper mold and the lower mold are closed, . 3. The method of claim 2,
Characterized by further comprising an actuator including a motor or a hydraulic cylinder for providing power for moving the support core portion between the first position and the second position, Injection molding mold. 3. The method of claim 2,
Wherein the product has a spout in which the female screw surface is formed on the inner surface,
Wherein the injection mold of the product having the female thread surface further comprises a plurality of slide cores which move so as to define the shape of the outer periphery of the spout when the upper mold and the lower mold are closed, Injection molds for products with female threads. 9. The method of claim 8,
At least one slide core of the plurality of slide cores is supported by the upper mold,
The slide core supported by the upper mold is in contact with the lower mold as the upper mold and the lower mold approach each other. When the upper mold and the lower mold come closer to each other, the slide core comes into contact with the lower mold, Moving toward a position defining the shape of the outer peripheral surface,
A slide core supported by the upper mold is provided with a hook so that the slide core supported by the upper mold when the upper mold and the lower mold are closed is held in close contact with the lower mold, Wherein the mold has a hook fastening step to be fastened to the hook. ≪ RTI ID = 0.0 > 11. < / RTI >

Images