JP2020121479A - Injection mold - Google Patents

Abstract

To provide an injection mold capable of equally splitting an injection resin to a plurality of gates, and realizing downsizing.SOLUTION: A first slide core 1A includes: an inlet runner R; a mold surface that transfers a surface shape onto an injection resin M; gates GA and GB that open at the mold surface; and a downstream runner communicating with the inlet runner Rand the gates GA and GB, and configured to split the injection resin M to the gates GA and GB. The downstream runner includes a first runner Rand a second runner R. The first runner Rincludes an opening 2b and a first circular pipe-shaped channel. The first circular pipe-shaped channel faces the gates GA and GB and extends along an alignment of the gate GA and GB. The second runner Rhas a channel cross section with higher resistivity than that of the first runner Rso that time of arrival from the opening 2b to the gates GA and GB is equalized.SELECTED DRAWING: Figure 3

Description

The present invention relates to an injection mold.

In injection molding using a plurality of gates, it is preferable that the resin enters from each gate substantially uniformly in the molding space. If the balance of the resin filled in the molding space is lost, good molding may not be performed.
In injection molding using a plurality of gates, the injection resin is divided into each gate through a runner having a branch flow path. Patent Document 1 proposes a technique for equalizing the arrival time of the injection resin to each gate by making the lengths of the flow paths in the branch flow path equal to each other.

JP, 2016-25240, A

However, the related art as described above has the following problems.
In the technique described in Patent Document 1, a flow path from the resin injection port to a nearby gate is provided for the purpose of making the lengths of the branch flow paths equal to each other regardless of the distance from the resin injection port to the separation flow path to the gate. It is curved.
However, the space in which a curved flow path can be formed in the mold is limited. When the space of the flow path is insufficient, there is a problem that the mold has to be upsized. In this case, the die cost increases. In addition, the length of the runner increases, so the amount of resin consumed also increases.
It may be possible to bend the runner to secure the length of the runner for the purpose of avoiding the enlargement of the mold, but in this case, the machining of the mold becomes complicated and the manufacturing cost of the mold increases. ..
For example, when arranging the gates in the axial direction in a long molded product, the variation in the shortest distance from the resin injection port to each gate is significantly large. The closer the gate is to the resin injection port, the longer the flow path needs to be accommodated in the narrow region. Further, since the flow path toward the farther gate needs to be formed so as to avoid the curved flow path closer to the gate, the flow path toward the farther gate also needs to be curved. As a result, the length of each flow path is increased, so that the size of the mold is likely to increase.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an injection molding die that can evenly divide an injection resin into a plurality of gates and can be downsized.

In order to solve the above problems, the injection mold of the first aspect of the present invention is an upstream runner having an injection port into which an injection resin is injected, a molding surface for transferring a surface shape to the injection resin, A plurality of gates that open in the molding surface, and a downstream runner that communicates with the upstream runner and the plurality of gates, respectively, and divides the injection resin injected into the injection port into each of the plurality of gates. The downstream runner has an opening through which the injection resin injected into the injection port flows, and a first circular tubular flow path having a first inner diameter, and the opening is the first circular tubular flow path. A first runner portion that is open to the passage, the first circular tubular flow path faces the plurality of gates, and extends along the row of the plurality of gates; and the first runner portion and the plurality of gates. A second runner portion that communicates with each of the first runner portions and that has a flow passage cross section having a resistance higher than that of the first runner portion to equalize the arrival time from the opening to each of the plurality of gates. ..

In the injection molding die, the second runner portion includes a plate-like flow path having a slit that opens to the first runner portion, and the size of the slit and the flow path in the thickness direction of the plate-like flow path. The width may be smaller than the first inner diameter.

In the injection-molding die, the downstream runner communicates with the second runner portion and each of the plurality of gates, and has a second circular tubular flow passage having a flow passage cross section having a lower resistance than the second runner portion. You may further include the 3rd runner part which has.

In the injection molding die, the opening is formed at an intermediate portion in the extending direction of the first circular tubular flow passage, and the first circular tubular flow passage is separated from the intermediate portion in the extending direction. Accordingly, in the facing direction with respect to the plurality of gates, the first circular tubular flow path may be curved in a concave shape approaching the plurality of gates.

In the injection molding die, the opening is formed at an intermediate portion in the extending direction of the first circular tubular flow path, and the length of the second runner portion in the facing direction with respect to the plurality of gates is It may become shorter as it goes away from the intermediate portion in the extending direction.

In the injection molding die, the opening is formed in an intermediate portion in the extending direction of the first circular tubular flow passage, and the size and the flow passage width are from the intermediate portion in the extending direction. It may grow larger with distance.

In the injection molding die, the opening is formed at a first end portion in the extending direction of the first circular tubular flow channel, and the first circular tubular flow channel is the first circular tubular flow channel. The distance between the rows of the plurality of gates is arranged so as to decrease from the first end toward a second end opposite to the first end, and the length of the second runner part is reduced. The length may become shorter as the distance from the first end portion increases in the extending direction.

The injection molding die according to the second aspect of the present invention includes an upstream runner having an injection port for injecting injection resin, a molding surface for transferring a surface shape to the injection resin, and a plurality of gates opened in the molding surface. And a downstream runner that communicates with each of the upstream runner and the plurality of gates and divides the injection resin injected into the injection port into each of the plurality of gates, wherein the downstream runner is the injection port. And a first circular tubular flow channel having a first inner diameter, wherein the opening is open to the first circular tubular flow channel, and The 1-circle tubular flow path communicates with each of the first runner portion and each of the plurality of gates, the first runner portion facing the plurality of gates and extending along an array of the plurality of gates, A second runner having a flow passage cross section having a higher resistance than that of the first runner portion, and respective shortest distances from the first runner toward the plurality of gates differ depending on respective shortest distances from the opening to the plurality of gates. And a part.

According to the injection molding die of the present invention, the injection resin can be evenly distributed to the plurality of gates, and the size can be reduced.

It is a typical perspective view showing an example of an injection mold of a 1st embodiment of the present invention. FIG. 3 is a schematic partial cross-sectional view of a molded product manufactured by the injection molding die according to the first embodiment of the present invention. It is a schematic front view of the injection-molding die of the 1st Embodiment of this invention. FIG. 3 is a sectional view taken along line AA in FIG. 2. It is explanatory drawing of the flow of the injection resin in the injection mold of the 1st Embodiment of this invention. It is a typical sectional view of the important section of the injection molding metallic mold of the 2nd embodiment of the present invention. It is a typical front view showing the principal part of the injection molding metallic mold of the 3rd embodiment of the present invention. It is a typical front view which shows an example of the principal part of the injection mold of the 4th Embodiment of this invention. It is CC sectional drawing in FIG. It is a typical front view which shows an example of the principal part of the injection molding metal mold|die of the 5th Embodiment of this invention. It is a typical front view which shows an example of the principal part of the injection mold of the 6th Embodiment of this invention.

Embodiments of the present invention will be described below with reference to the accompanying drawings. In all the drawings, the same or corresponding members are denoted by the same reference numerals even if the embodiments are different, and common description is omitted.

[First Embodiment]
The injection molding die according to the first embodiment of the present invention will be described.
FIG. 1 is a schematic perspective view showing an example of an injection molding die according to the first embodiment of the present invention. FIG. 2 is a schematic partial cross-sectional view of a molded product manufactured by the injection molding die according to the first embodiment of the present invention. FIG. 3 is a schematic front view of the injection molding die according to the first embodiment of the present invention. FIG. 4 is a sectional view taken along line AA in FIG.

The shape of the molded product manufactured by the injection molding die of the present embodiment is not particularly limited. The shape of the molded product may be, for example, a box shape, a cylinder shape, a rod shape, a plate shape, a frame shape, a net shape, or the like.
The mold configuration of the injection molding die of the present embodiment can be appropriately selected according to the shape of the molded product manufactured by the injection molding die. For example, the mold configuration of the injection mold may or may not have the slide core.
Hereinafter, an example in the case of the injection mold 1 for manufacturing the molded product 54 (see FIG. 2) shown in FIG. 1 will be described.

As shown in FIG. 1, the injection molding die 1 of this embodiment includes a first slide core 1A, a second slide core 1B, and a core 1C. Although not particularly shown, the injection molding die 1 further includes known members such as a fixed-side mold plate, a cavity mold, and a movable-side mold plate.
The injection mold 1 is used for the purpose of manufacturing a molded product 54 by injection molding.
For example, the molded product 54 can have any suitable shape including a tubular portion and a plurality of thick portions protruding from the tubular portion.
The wall thickness of the tubular portion is constant in the axial direction of the tubular portion. The cross-sectional shape of the tubular portion is not particularly limited. For example, the cross-sectional shape of the tubular portion may be a circle, an ellipse, a polygon, a half moon, or the like.
The plurality of thick portions may have the same shape or may not have the same shape. The specific shape of each thick portion is not particularly limited. For example, the shape of the thick portion may be trapezoidal, strip-shaped, dot-shaped, rod-shaped, dome-shaped, or the like. For example, the shape of the thick portion may be a plate shape such as a flange shape, a fin shape, or a screw shape.
The plurality of thick portions are arranged apart from each other in at least one of the axial direction and the circumferential direction of the tubular portion.
The molded product 54 may be provided with a protrusion that does not correspond to the above-mentioned thick portion.
Hereinafter, as an example, a case where the molded product 54 has a shape shown in FIGS. 1 and 2 will be described.

In the example shown in FIG. 2, the molded product 54 has a tubular portion 54a, a protruding portion 54b, and a flange portion 54c.
The tubular portion 54a is a cylinder extending along the central axis O. The inner diameter of the tubular portion 54a is D, the wall thickness is t, and the length is L.
For example, L may be 50 mm or more. D may be 5 mm or more and 50 mm or less. t may be 0.1 mm or more and 2 mm or less.

The protruding portion 54b projects in the radial direction from the outer peripheral surface 54d of the tubular portion 54a over the entire circumference of the outer peripheral surface 54d. The shape of the protrusion 54b in a cross section including the central axis O is a w1×h1 rectangle. Here, w1 represents the axial width, and h1 represents the protrusion height from the outer peripheral surface 54d. The tip end surface of the protruding portion 54b in the protruding direction is a cylindrical surface coaxial with the central axis O. The outer diameter of the tip surface of the protrusion 54b is (D+t+h1). In the axial range in which the protrusion 54b is formed, the thickness of the molded product 54 is t+h1.
The sizes of w1 and h1 are not particularly limited. For example, in the example shown in FIG. 2, t<h1<w1.

The flange portion 54c has the same shape as the protrusion portion 54b except that the size of the cross section including the central axis O is different.
The shape of the flange portion 54c in a cross section including the central axis O is a w2×h2 rectangle. In the example shown in FIG. 2, t<w2<w1 and h1<h2. Here, w2 represents the width in the axial direction, and h2 represents the protrusion height from the outer peripheral surface 54d. The tip end surface of the flange portion 54c in the projecting direction is a cylindrical surface coaxial with the central axis O. The outer diameter of the front end surface of the flange portion 54c is D+t+h2.

As described above, in the example shown in FIG. 2, the protrusion 54b is a strip-shaped protrusion extending on the outer peripheral surface 54d in the circumferential direction. On the other hand, the flange portion 54c is a plate-shaped projection that protrudes radially outward from the outer peripheral surface 54d along a plane orthogonal to the central axis O, in a ring shape.
It can be said that the protrusion 54b itself is a thick portion. However, since the aspect ratio of the protruding shape is low, it can be said that the protruding portion 54b is a thick portion in which the cylindrical shape has an uneven thickness, depending on the specific size of h1 and w1.
On the other hand, since the flange portion 54c has a high aspect ratio in the protruding shape, the flange portion 54c itself is a plate-shaped thicker portion than the tubular portion 54a.

The number and the arrangement interval of the protrusions 54b and the flanges 54c are not particularly limited.
In the example shown in FIG. 2, three protrusions 54b and two flanges 54c are formed. The protrusions 54b and the flanges 54c are arranged alternately in the axial direction of the tubular portion 54a. The arrangement interval between the protrusion 54b and the flange 54c is a constant value LT.

The protrusion 54b and the flange 54c described above have an undercut shape in the case of a die configuration in which the axial direction of the molded product 54 is the pulling direction.
The thick portion may project from the inner peripheral surface 54e. However, in the example shown in FIG. 2, no protrusion is formed on the inner peripheral surface 54e.

The material of the molded product 54 is not particularly limited as long as it is a resin material that can be injection-molded. The material of the molded product 54 may be a hard resin material or a soft resin material such as an elastomer.

Next, the injection mold 1 of this embodiment will be described.
In the following, description may be made with reference to the XYZ orthogonal coordinate system shown in FIG. The Z axis is an axis extending in the moving direction of the movable mold plate or the like. The X axis is an axis line orthogonal to the Z axis. The Y axis is an axis line that is orthogonal to the X axis in a plane that includes the X axis and is orthogonal to the Z axis. The directions along the X axis, the Y axis, and the Z axis are referred to as the X direction, the Y direction, and the Z direction, respectively.

The first slide core 1A and the second slide core 1B are arranged to face each other in the Y direction. The first slide core 1A and the second slide core 1B are slidable in at least the Y direction when the injection molding die 1 is opened and closed.
The core 1C is arranged along an axis parallel to the Z axis. The core 1C is fixed to the movable-side template and is movable in the Z direction together with the movable-side template.

The first slide core 1A and the second slide core 1B form the shape of the outer peripheral portion of the molded product 54.
The shapes of the first slide core 1A and the second slide core 1B are plane-symmetric with respect to a plane parallel to the ZX plane. Hereinafter, the shape of the first slide core 1A will be mainly described.

The outer shape of the first slide core 1A is a substantially rectangular parallelepiped elongated in the Z direction. A first end face 1a parallel to the XY plane is formed at the Z-direction end of the first slide core 1A. The first end surface 1a faces a fixed-side mold plate (not shown) of the injection mold 1 when the mold is closed.
A second end face 1b parallel to the XY plane is formed at the end opposite to the first end face 1a in the Z direction. The second end surface 1b is in contact with a movable side mold plate (not shown) in the injection molding die 1 when the mold is closed.
A parting surface 1c is formed on the surface of the first slide core 1A facing the second slide core 1B. The parting surface 1c is a plane parallel to the XZ plane.

Each parting surface 1c is formed with a recess that forms the outer shape of the molded product 54 when the injection molding die 1 is closed. A molding space for molding the molded product 54 is formed between the recess and the core 1C. The concave portion (molding surface) forming a part of the molding space forms the outer shape of the molded product 54 by transferring the surface shape thereof to the injection resin filled in the molding space.
Each parting surface 1c is formed with a recess that forms a resin flow path for filling the molding space with the molding resin.
The concave portion forming the molding space includes a cylindrical portion molding surface 4a (molding surface), a protrusion molding surface 4b (molding surface), and a flange molding surface 4c (molding surface).
The concave portion forming the resin flow passage is composed of a first resin flow passage portion P1 and a second resin flow passage portion P2.

The cylindrical portion molding surface 4a forms the shape of a half circumference portion of the outer peripheral surface 54d of the tubular portion 54a. The cylindrical portion molding surface 4a is a semicircular groove extending in the Z direction about the central axis OA. In the present specification, the semicircular groove is defined as a groove having a semicircular cross-sectional shape orthogonal to the extending direction. In the semicircular groove, the radius of the semicircle in the cross section is called the groove radius.
The central axis OA extends parallel to the Z axis at the center of the parting surface 1c.
The groove radius of the cylindrical portion molding surface 4a is D/2. The cylindrical portion molding surface 4a penetrates between the first end surface 1a and the second end surface 1b in the Z direction. The length of the cylindrical portion molding surface 4a is equal to the total length L of the molded product 54.

As shown in FIG. 3, the projection molding surface 4b and the flange molding surface 4c are recesses formed on the parting surface 1c and the cylindrical molding surface 4a.

The protruding portion molding surface 4b forms the protruding portion 54b of the molded product 54. The protruding portion molding surface 4b is formed at three locations in correspondence with the number and arrangement of the protruding portions 54b. The shape of the protruding portion molding surface 4b corresponds to the outer shape of the protruding portion 54b. Specifically, the shape of the protrusion forming surface 4b is a square groove having a width w1 in the Z direction and a depth h1 from the protrusion forming surface 4b.
The protrusion forming surface 4b extends in a semicircular shape in a plane parallel to the XY plane. The groove bottom surface of the protrusion forming surface 4b is a cylindrical surface having a radius (D+t+h1) from the central axis OA.

The flange portion molding surface 4c forms the flange portion 54c of the molded product 54. The flange portion molding surface 4c is formed at two locations corresponding to the number and arrangement of the flange portions 54c. The shape of the flange molding surface 4c corresponds to the outer shape of the flange 54c. Specifically, the shape of the flange molding surface 4c is a square groove having a width w2 in the Z direction and a depth h2 from the projection molding surface 4b.
The flange portion molding surface 4c extends in a semicircular shape in a plane parallel to the XY plane. The groove bottom surface of the flange portion molding surface 4c is a cylindrical surface whose radius from the central axis OA is (D+t+h2).

As shown in FIG. 1, the core 1C is a columnar member having a cylindrical outer peripheral surface 1d. The core 1C forms the shape of the inner peripheral surface 54e of the molded product 54.
The outer diameter of the outer peripheral surface 1d of the core 1C is D corresponding to the outer diameter of the inner peripheral surface 54e. The length of the core 1C is L corresponding to the length of the tubular portion 54a.
The end faces 1e, 1f formed at both ends in the axial direction of the core 1C are planes orthogonal to the central axis OC of the outer peripheral face 1d.

As shown in FIG. 3, also on the parting surface 1c of the second slide core 1B, with the central axis OB as the center, similar to the first slide core 1A, the cylindrical surface molding surface 4a, the projection surface 4b, and the flange portion. A molding surface 4c is formed. However, the coordinate system in FIG. 3 indicates the attitude of the first slide core 1A.
When the parting surfaces 1c of the first slide core 1A and the second slide core 1B come into contact with each other when the injection molding die 1 is closed, the central axes OA and OB are arranged coaxially. At this time, the cylindrical molding surfaces 4a, the protrusion molding surfaces 4b, and the flange molding surfaces 4c that face each other in the Y direction form the shape of the outer peripheral surface of the molded product 54.
As shown by the chain double-dashed line, the core 1C is inserted in the Z direction at the center of the internal space surrounded by the cylindrical surface 4a. The end faces 1e and 1f of the core 1C are flush with the first end face 1a and the second end face 1b of the first slide core 1A and the second slide core 1B, respectively.
As a result, a molding space S surrounded by the outer peripheral surface 1d of the core 1C, each cylindrical portion molding surface 4a, each projection portion molding surface 4b, and each flange portion molding surface 4c is formed.

The first resin flow path portion P1 and the second resin flow path portion P2 have plane-symmetric shapes with respect to a plane that passes through the central axis OA and that is parallel to the YZ plane. Below, it demonstrates centering around the shape of the 1st resin flow path part P1.

The first resin flow path portion P1 includes an inlet runner groove 2A, a first runner groove 2B, a second runner groove 2C, a third runner groove 2D, and gate grooves 3A and 3B.

The inlet runner groove 2A is a semicircular groove extending between the inlet 2a and the opening 2b. The groove radius of the inlet runner groove 2A is constant.
The inlet 2a is a semicircular opening provided for the purpose of injecting the injection resin M into the inlet runner groove 2A. The inlet 2a is open to the first end face 1a.
The opening 2b is formed at a position facing the central protrusion forming surface 4b among the three protrusion forming surfaces 4b in the X direction. The center of the opening 2b coincides with the center of the protrusion molding surface 4b in the width direction (Z direction). Below, the plane parallel to the XY plane that passes through the center of the opening 2b is referred to as the reference plane m. In this embodiment, the distance from the reference surface m to the center of each flange portion molding surface 4c in the width direction is LT. The distance from the reference surface m to the center in the width direction of each protrusion molding surface 4b through which the reference surface m does not pass is 2×LT.

The path of the inlet runner groove 2A is not particularly limited. In the example shown in FIG. 3, the inlet runner groove 2A extends in the Z direction from the inlet 2a, bends in the X direction away from the central axis OA, bends in the Z direction toward the reference plane m, and forms the opening 2b. It is formed along a path that bends in the X direction toward the opening 2b at the opposing position.
The inner diameter of the inlet runner groove 2A is set to an appropriate size so that the molten injection resin M can flow well.

The first runner groove 2B is a semi-circular groove along a path curved in a concave shape toward the central axis OA. Both ends of the first runner groove 2B in the extending direction extend to positions opposite to the gate grooves 3A, which will be described later, on the both sides of the reference surface m and farthest from the reference surface m in the X direction. It has been overrun. The first runner groove 2B is plane-symmetric with respect to the reference plane m.
The curved shape of the first runner groove 2B is set for the purpose of changing the length in the X direction of the second runner groove 2C described later in the Z direction.
As shown in FIG. 4, the groove radius of the first runner groove 2B is a constant value rB.

As shown in FIG. 4, the second runner groove 2C is a recess communicating with the side surface of the first runner groove 2B that faces the third runner groove 2D described later. The depth of the second runner groove 2C from the parting surface 1c is tC (provided that tC<rB).
As shown in FIG. 3, the second runner groove 2C communicates with the first runner groove 2B over substantially the entire length of the first runner groove 2B in the extending direction. The width of the second runner groove 2C in the X direction changes in the Z direction according to the amount of bending of the first runner groove 2B. Further, the shape of the second runner groove 2C viewed in the Y direction is plane-symmetric with respect to the reference plane m.

The third runner groove 2D is a semicircular groove linearly extended in the X direction. The third runner groove 2D is formed at a position opposed to the entire first runner groove 2B in the X direction with the second runner groove 2C interposed therebetween. The second runner groove 2C communicates with the third runner groove 2D.
The length of the third runner groove 2D is the same as the length of the formation range of the first runner groove 2B in the Z direction. The center of the third runner groove 2D in the Z direction is located on the reference plane m.
As shown in FIG. 4, the groove radius of the third runner groove 2D is a constant value rD (where rD>tC).

The gate groove 3A is a recess that allows the protrusion forming surface 4b and the third runner groove 2D facing the protrusion forming surface 4b to communicate with each other in the X direction. The gate groove 3A is a semicircular groove centered on an axis extending in the X direction. For example, the gate groove 3A has a shape obtained by dividing the shape of the pin gate in half from the center. As shown in FIG. 4, at the tip of the gate groove 3A, a gate opening 3a that opens to the projection molding surface 4b and an appropriate land 3b that optimizes the speed of the injection resin M that enters the molding space S are formed. Has been done.
In the gate groove 3A, the radius of the opening 3c communicating with the third runner groove 2D is less than rD.
The gate groove 3A diverts the injection resin M flowing in the Z direction through the third runner groove 2D toward the protrusion molding surface 4b.

The gate groove 3B is a recess similar to the gate groove 3A except that the flange molding surface 4c and the third runner groove 2D communicate with each other. However, the length of the gate groove 3B is different from that of the gate groove 3A depending on the distance from the third runner groove 2D to the flange portion molding surface 4c that faces the third runner groove 2D in the X direction.
The gate groove 3B diverts the injection resin M flowing in the Z direction in the third runner groove 2D toward the flange portion molding surface 4c.

As shown in FIG. 3, the first resin flow path portion P1 and the second resin flow path portion P2 similar to those in the first slide core 1A are also formed on the parting surface 1c of the second slide core 1B.
When the parting surfaces 1c of the first slide core 1A and the second slide core 1B come into contact with each other when the injection molding die 1 is closed, the first resin flow path portions P1 and the second resin flow path portions P1 facing each other in the Y direction. The resin flow path portion P2 forms resin flow paths F1 and F2 each having a circular or rectangular flow path cross section.
The resin flow paths F1 and F2 are respectively an inlet runner R _2A (upstream runner), a first runner R _2B (downstream runner, a first circular tubular flow path, a first runner portion), a second runner R _2C (downstream runner, The second runner part, the plate-like flow path), the third runner R _2D (downstream runner, the second circular tubular flow path, the third runner part), and the gate GA, GB.

The inlet runner R _2A is a flow path formed by a combination of the inlet runner grooves 2A facing each other in the Y direction. The inlet runner R _2A constitutes an upstream runner having an injection port 2a into which the injection resin M is injected.
The first runner R _2B , the second runner R _2C , and the third runner R _{2D communicate} with the inlet runner R _2A and the gates GA and GB, respectively, and the injection resin M injected into the inlet 2 a is injected into the gate GA, respectively. Configure a downstream runner that splits into each of the GBs.

The first runner R _2B is a flow path formed by a combination of the first runners R _2B facing each other in the Y direction. The first runner R _2B is a first circular tubular flow path having a first inner diameter of 2×rB. Each opening 2b is opened at the central portion (intermediate portion) in the extending direction of the first runner R _2B . The first runner R _2B faces the gates GA and GB with the second runner R _2C and the third runner R _2D interposed therebetween, and extends along the alignment of the gates GA and GB.

The second runner R _2C is a flow path formed by a combination of the second runners R _2C facing each other in the Y direction. The second runner R _2C is a plate-like flow passage having a flow passage width of 2×tC in the thickness direction.
Due to the second runner R _2C , on the side surface of the first runner R _{2B in} the X direction, a slit SL1 having a width of 2×tC (FIG. 4) similar to the flow path width is formed over substantially the entire extending direction of the first runner R _2B . (See) is formed.
Since the channel width is narrower than the first inner diameter, the channel cross section of the second runner R _2C has a higher resistance than the channel cross section of the first runner R _2B .

As shown in FIG. 3, the length of the second runner R _2C in the facing direction (X direction) with respect to each of the gates GA and GB becomes shorter as the distance from the reference plane m increases in the extending direction of the first runner R _2B . For example, the length of the second runner R _{2C at} the portion facing the central gate GA (referred to as the first gate) in the Z direction is L0. The length of the second runner R _{2C at} the portion facing each gate GB arranged next to the central gate GA is L1 (where L1<L0). The length of the second runner R _2C at a portion facing each gate GA (referred to as a second gate) arranged farther from the reference plane m than each gate GA is L2 (where L2<L1).
The lengths L0, L1, and L2 are set to lengths such that the arrival time of the injection resin M from the opening 2b to the first gate, the gate GB, and the second gate becomes equal. Each length can be determined by, for example, a flow simulation of the injection resin M.

The third runner R _2D is a flow path formed by a combination of the third runners R _2D that face each other in the Y direction. The third runner R _2D is a second circular tubular flow path having a second inner diameter of 2×rD. Since the second inner diameter is larger than the flow passage width of the second runner R _2C , the flow passage cross section of the third runner R _2D has a lower resistance than the flow passage cross section of the second runner R _2C .
Due to the second runner R _2C , on the side surface of the third runner R _{2D in} the X direction, a slit having a width of 2×tC, which is similar to the flow path width, is formed over substantially the entire extending direction (Z direction) of the third runner R _2D. SL2 (see FIG. 4) is formed.

The gate GA is a flow path formed by a combination of the gate grooves 3A facing each other in the Y direction. The gate GB is a flow path formed by a combination of the gate grooves 3B facing each other in the Y direction.

With such a configuration, in the second runner R _2C , the shortest distance of the flow path from the first runner R _2B to each gate GA, GB differs depending on the shortest distance between the opening 2b and each gate GA, GB. There is. For example, in the second runner R _2C , the shortest distance in the flow path from the first runner R _2B to the first gate, which is closest to the opening 2b, is L0. In contrast, the first runner R _2B in which the shortest distance from the opening 2b is sequentially _lengthened, in the flow path of the second runner R _2C toward the second gate, the shortest distance towards the gates from the first runner R _2B , L1 and L2, the shorter the shortest distance from the opening 2b to each gate, the shorter the distance.

A manufacturing process of the molded product 54 using the injection molding die 1 will be described.
FIG. 5: is explanatory drawing of the flow of the injection resin in the injection mold of the 1st Embodiment of this invention.

When manufacturing the molded product 54, the injection mold 1 is attached to an injection molding machine (not shown). When the injection molding die 1 is closed, the molding space S is formed inside the assembly including the first slide core 1A, the second slide core 1B, and the core 1C, and the projection molding surface 4b is formed in the molding space S. , Resin flow paths F1 and F2 communicating with each other through the flange portion molding surface 4c are formed.
Each injection port 2a in the first end face 1a of the resin flow paths F1 and F2 communicates with a sprue (not shown) in a cavity template (not shown).
The injection resin M injected in a molten state from the injection molding machine is injected into the resin flow paths F1 and F2 through the sprue and the injection ports 2a. The injection amount of the injection resin M is predetermined according to the total volume of the molding space S and the resin flow paths F1 and F2.

The resin flow paths F1 and F2 are similar to each other except that the arrangement positions are different. Therefore, the resin flow path F1 will be described below as an example.
As shown in FIG. 5, the injection resin M injected from the injection port 2a of the resin flow path F1 flows in the inlet runner R _2A along the route toward the opening 2b. In the vicinity of the opening 2b, the injection resin M flows in the X direction where the end portion of the inlet runner R _2A extends.
When the injection resin M enters the first runner R _2B through the opening 2b, it flows toward both ends of the first runner R _2B (see long arrow). Since the first runner R _2B extends in the Z direction in the vicinity of the opening 2b, a T-shaped branch flow path that branches in two directions from the X direction to the Z direction is formed in the vicinity of the opening 2b. Therefore, the flow of the injected resin M is a first runner R _2B toward the first end face 1a, is bisected in both the first runner R _2B toward the second end face 1b.
The side surface of the first runner _{R 2B,} since the slits SL1 is opened, part of the resin MC of injected resin M, through the slit SL1, flows into the second runner _{R 2C.}
However, the opening width (Y direction width) of the slit SL1 is smaller than the first inner diameter of the first runner _{R 2B,} the flow path resistance of the second runner _{R 2C} is a flow path resistance of the first runner _{R 2B} Big compared to. As a result, the resin MB other than the resin MC in the injection resin M flows in the extending direction of the first runner R _2B . The amount of resin MB is much larger than that of resin MC.

The flow velocity of the resin MC is lower than the flow velocity of the resin MB due to the difference in the size of the flow passage cross section in the flow direction. Therefore, the resin MC is filled in the first runner R _2B before the resin MC passes through the third runner R _2D and flows into the gates GA and GB. After the completion of filling the first runner R _2B with the injection resin M (hereinafter referred to as the first filling completion), a substantially uniform injection pressure is applied to the entire injection resin M in the first runner R _2B . Therefore, the injection resin M is entirely extruded into the second runner R _2C from the slit SL1.

The resin MC gradually flows into the second runner R _2C until the completion of the first filling. The resin MB is charged into the first runner R _2B is, since it takes a time corresponding to the length of the first runner R _2B, timings of the resin MC that flows into the second runner R _2C is Z from the reference plane m The farther you go, the slower it gets. The pressure applied to the resin MC is lower as it goes away from the reference plane m in the Z direction. As a result, the amount of the resin MC flowing into the second runner R _2C becomes smaller as it goes away from the reference plane m in the Z direction. Similarly, the flow velocity of the resin MC decreases as the distance from the reference surface m increases in the Z direction.
Therefore, when the first runner R _2B has a linear shape, the resin MC that travels in the second runner R _2C spreads in a fan shape having the longest flow length on the reference surface m. However, in the present embodiment, since the first runner R _2B is curved concavely toward the third runner R _2D , the tip end surface of the resin MC is flattened according to the amount of bending. Therefore, by appropriately setting the magnitude of the resistance of the flow passage cross section of the second runner R _2C and the bending amount of the first runner R _2B , the difference in the filling time in the Z direction of the second runner R _2C can be reduced. can do.
Incidentally, as in this embodiment, amount of curvature of the outlet third case straight along the runner R _2D first runner R _2B in the second runner R _2C is first in the extending direction of the first runner R _2B 2 It defines the distribution of the flow path length of the runner R _2C .

In this way, the tip of the resin MC is flattened in the X direction as it advances toward the third runner R _2D . As a result, at each position in the Z direction, the second runner R _2C is filled almost simultaneously. Hereinafter, the time when the filling of the second runner R _2C is completed is referred to as the time when the second filling is completed.

The resin MC flowing into the second runner R _2C is turbulent before the completion of the first filling. When the length of the second runner R _2C in the X direction is shortened for the purpose of further downsizing the injection molding die 1, it is considered that the position of the tip end surface of the resin MC in the X direction varies to some extent in the Z direction.
In the present embodiment, the downstream runner is provided with the third runner R _2D to reduce the deviation of the arrival timing of the injection resin M to the gates GA and GB due to the disturbance of the front end surface of the resin MC.
The resin MC that has crossed the second runner R _2C in the X direction flows into the third runner R _2D through the slit SL2. The second inner diameter of the third runner R _2D is larger than the opening width (width in the Y direction) of the slit SL2. Resin MD entering the third runner _{R 2D} is, when injected into the third runner _R in _2D, dispersed in the third runner _R in _2D, and the flow rate is reduced.
As a result, the resin MD is filled into the third runner R _2D to some extent, and then flows into the molding space S from the nearby gate.
As a result, even if the inflow amount of the resin MD in the longitudinal direction of the third runner R _2D varies due to the variation of the tip end surface of the resin MC, the time for the resin MD to reach each gate is equalized.

As described above, in this embodiment, the gates GA and GB have the same arrival time of the injection resin M even if the positions in the Z direction are different.
After the third runner R _2D is filled with the injection resin M, a substantially uniform injection pressure is applied to the entire injection resin M in the downstream runner, so that the injection resin is sequentially injected into the molding space S through the gates GA and GB. M is filled evenly.

The injection resin M filled in the molding space S is cooled by heat conduction to the first slide core 1A, the second slide core 1B, and the core 1C. When the injection resin M is left for a time such that the temperature of the injection resin M becomes equal to or lower than the glass transition point, a molded body 50 in which the injection resin M in the injection molding die 1 is solidified is formed as shown in FIG. Thereafter, the mold opening of the injection molding die 1 is executed.

When the injection mold 1 is opened, the first slide core 1A and the second slide core 1B are separated from each other in the Y direction. This allows the molded body 50 to be released from the mold.
The molded body 50 includes a molded product 54 and flow path resin portions Q1 and Q2.
The flow path resin portion Q1 is formed by solidifying the injection resin M filled in the resin flow path F1. The flow path resin portion Q1 includes a runner resin portion 52 and gate resin portions 53A and 53B. The runner resin portion 52 is a portion to which the shapes of the upstream runner and the downstream runner are transferred. The gate resin portions 53A and 53B are portions to which the shapes of the gates GA and GB are transferred, respectively.
The flow path resin portion Q2 is formed by solidifying the injection resin M filled in the resin flow path F2. The flow channel resin portion Q2 is composed of a runner resin portion 52 and gate resin portions 53A and 53B, like the flow channel resin portion Q1.
The molded article 54 is manufactured by separating the flow path resin portions Q1 and Q2 from the molded body 50.

According to the injection molding die 1, the downstream runner is provided with the first runner R _2B , the second runner R _2C , and the third runner R _2D having different resistances in the cross section of the flow path, so that the injection resin M The gates GA and GB can be evenly distributed. At this time, since the arrival times of the gates GA and GB from the opening 2b are equalized, the supply amounts of the injection resin M from the gates GA and GB are also equalized.
In the present embodiment, the first runner R _2B , the second runner R _2C , and the third runner R _2D consist of a continuous flow path, and the flow path of the injection resin M from the opening 2b to the gates GA and GB. The length is not uniform. For example, the typical length of the flow path from the opening 2b to the first gate (hereinafter referred to as the central flow path) is (2×rB+L0+2×rD). On the other hand, the typical length of the flow path from the opening 2b to the second gate (hereinafter referred to as the end flow path) is larger than (2×LT+L2+2×rD). For this reason, the end channel is much longer in the end channel than in the central channel.
However, the central flow path is dominated by the second runner R _2C having high resistance and low flow velocity, whereas the end flow path has low resistance and high flow velocity. The runner R _2B occupies the majority, and the length passing through the second runner R _2C is short. As a result, the arrival times from the openings 2b to the respective gates become equal to each other.

In the injection molding die 1 of the present embodiment, since the long end passages are arranged in the longitudinal direction of the molding space S, the entire downstream runner is formed in the elongated rectangular range in the longitudinal direction of the molding space S. ing. As a result, the size of the injection molding die 1 in the X direction becomes compact.
For example, in the case of the comparative example in which a plurality of flow passages of equal length are provided between the injection port of the injection resin M and each gate, if the gates are arranged in one row, each flow passage is curved and It is necessary to avoid interference between the flow paths. As a result, as the number of gates increases, a wider flow path space is required in the direction orthogonal to the gates. However, in this embodiment, the flow passage space as in the comparative example is unnecessary.
Further, in the case of the comparative example, if the gates are closely packed, it becomes more difficult to secure the flow path space, but in the present embodiment, even if the gates are more closely packed, the same downstream runner can be used.

According to the injection molding die 1 of the present embodiment, the injection resin can be evenly distributed to the plurality of gates, and the size can be reduced.
In particular, by providing the third runner R _2D, as described above, as compared to the case not having a third runner R _2D, it is possible to a second runner R _2C shortened by the X-direction.

According to the injection molding die 1, the gates GA and GB are opened in the projection 54b forming the thick portion of the molded product 54, the projection molding surface 4b molding the flange 54c, and the flange molding surface 4c, respectively. doing.
As a result, the injection resin M is filled from the molding space S corresponding to the thick portions such as the protrusion 54b and the outer peripheral surface 54d of the molded product 54. In this case, the injection resin M flows in the molding space S from a space having a small flow resistance corresponding to one thick portion to a space having a large flow resistance corresponding to a thinner tubular portion. As a result, turbulent flow is unlikely to occur at the tip end surface of the injection resin M in the flow direction.
Furthermore, since the injection resin M is first filled in the space corresponding to the thick portion where insufficient filling is likely to occur, insufficient filling of the thick portion can be prevented.
Since a plurality of gates GA and GB are provided along the longitudinal direction of the molding space S, compared to the case where a gate is provided at the axial end of the molding space S, the injection resin M filled from one gate is filled. Has a shorter flow length. As a result, the temperature drop of the injection resin M at the tip portion in the flow direction becomes smaller, so that the filling of the injection resin M can be completed while the viscosity of the injection resin M is low. This improves the dimensional accuracy of the molded product 54.

[Second Embodiment]
An injection molding die according to the second embodiment of the present invention will be described.
FIG. 6 is a schematic cross-sectional view of a main part of an injection molding die according to the second embodiment of the present invention.

As shown in FIG. 1, the injection mold 11 of this embodiment produces a molded product 54 (see FIG. 2) similar to that of the first embodiment.
The injection molding die 11 includes a first slide core 11A and a second slide core 11B instead of the first slide core 1A and the second slide core 1B in the injection molding die 1 of the first embodiment. The first slide core 11A includes a first resin flow path portion P11 instead of the first resin flow path portion P1 of the first slide core 1A. The second slide core 11B includes a second resin flow path portion P12 instead of the second resin flow path portion P2 of the second slide core 1B.
Hereinafter, the points different from the first embodiment will be mainly described.

As shown in FIG. 3, the first resin flow path portion P11 and the second resin flow path portion P12 have plane-symmetric shapes with respect to a plane that passes through the central axis OA and is parallel to the YZ plane. Below, it demonstrates centering around the shape of the 1st resin flow path part P11.

The first resin flow path portion P11 includes a second runner groove 12C instead of the second runner groove 2C in the first resin flow path portion P1.
As shown in FIG. 6, the second runner groove 12C includes an inlet runner groove 2A and a gate groove 13C. FIG. 6 is a sectional view taken along line BB in FIG.
The second runner groove 12C differs from the second runner groove 2C in the first embodiment only in the groove depth. The depth of the second runner groove 12C from the parting surface 1c is t1 at the center in the Z direction intersecting with the reference surface m and t2 at both ends in the Z direction (however, t1<t2<rB, t2<rD). Is. The depth from the center in the Z direction to both ends gradually increases from t1 to t2 as the distance from the reference plane m increases.

With such a configuration, when the parting surfaces 1c of the first slide core 11A and the second slide core 11B come into contact with each other when the injection mold 11 is closed, the second runner grooves 12C facing each other in the Y direction. Forms a flow path cross section such as the cross section of a biconcave lens, as shown by the solid and two-dot chain lines in FIG. As a result, a second runner R _12C (downstream runner) surrounded by each second runner groove 12C is formed instead of the second runner R _2C in the first embodiment.

The injection mold 11 differs from the injection mold 1 in that the resistance of the flow passage cross section in the second runner R _12C changes in the Z direction.
In the second runner R _12C , since the flow passage cross section near the reference plane m is the smallest, the flow passage resistance is the maximum. The flow path resistance of the second runner R _12C decreases with increasing distance from the reference plane m in the Z direction, and becomes minimum at both ends in the Z direction.
As a result, the flow velocity of the resin MC in the second runner R _12C until the completion of the first filling increases as the distance from the reference surface m increases. As a result, the time required for the resin MC to reach the second gate in the end channel can be shortened. For this reason, it is not necessary to lengthen the central flow path in order to balance the arrival times, so that the arrival times of the injection resin M can be equalized without increasing the size of the injection mold 11 in the X direction.

According to the injection molding die 11 of the present embodiment, as in the first embodiment, the injection resin can be evenly distributed to a plurality of gates, and the size can be reduced.
In particular, in the present embodiment, even when the bending amount of the first runner R _2B cannot be made too large, it is possible to obtain a larger value by changing the magnitude of the resistance of the flow passage cross section of the second runner R _{12C in} the Z direction. An effect equivalent to that of forming a curve is obtained. Therefore, the injection mold 11 can be further downsized as compared with the injection mold 1 of the first embodiment.

[Third Embodiment]
An injection molding die according to the third embodiment of the present invention will be described.
FIG. 7 is a schematic front view showing a main part of an injection molding die according to the third embodiment of the present invention.

The injection-molding die 21 of the present embodiment, the main part of which is shown in FIG. 7, manufactures a molded product 54 (see FIG. 2) similar to that of the first embodiment.
The injection molding die 21 includes a first slide core 21A instead of the first slide core 1A in the injection molding die 1 of the first embodiment. Although illustration is omitted, the injection molding die 21 includes a second slide core having the same configuration as the first slide core 21A, instead of the second slide core 1B in the first embodiment.
The first slide core 21A includes a first resin flow path portion P21 instead of the first resin flow path portion P1 of the first slide core 1A. Although illustration is omitted, the first slide core 21A further includes a second resin flow path portion. The second resin flow path portion has a plane-symmetrical shape with a plane that passes through the central axis OA and is parallel to the YZ plane as a plane of symmetry.
Hereinafter, the points different from the first embodiment will be mainly described.

The first resin flow path portion P21 includes a second runner groove 22C instead of the second runner groove 2C in the first resin flow path portion P1.
The second runner groove 22C is composed of a plurality of semicircular grooves 22c that communicate with the first runner groove 2B and the third runner groove 2D. Each semicircular groove 22c extends in the X direction. However, at least a part of each semicircular groove 22c may extend in a direction oblique to the X direction on the ZX plane.
The groove radius of each semicircular groove 22c is a constant value rC (where rC<rB and rC<rD). However, the groove radius of each semicircular groove 22c may be changed in the Z direction. For example, the groove radius of each semicircular groove 22c may increase as the distance from the reference surface m increases.
The number of the semicircular grooves 22c is not particularly limited as long as it is larger than the number of the gates GA and GB. It is more preferable that the number of the semicircular grooves 22c is twice or more that of each of the gates GA and GB.
In the example shown in FIG. 7, the semicircular grooves 22c are arranged at equal intervals in the Z direction. However, the array density per unit length of the semicircular groove 22c in the Z direction may change in the Z direction. For example, the arrangement density of the semicircular grooves 22c may increase as the distance from the reference plane m increases. Particularly, it is more preferable that the semicircular groove 22c is not formed on the reference surface m.

With this configuration, when the parting surfaces 1c of the first slide core 21A and the second slide core (not shown) come into contact with each other when the injection mold 21 is closed, the second runner grooves 22C are moved in the Y-direction. The semicircular grooves 22c facing each other have a second runner Ri (where i=1, 2,..., N, n is an integer of 5 or more) having a circular flow path cross section (downstream runner, second runner portion). Form.

In the first embodiment, the flow path of the second runner R _2C is continuous in the Z direction, whereas each of the second runners Ri has a circular cross section, and in the Z direction, The difference is that they are not in communication with each other. The injection resin M flowing in each second runner Ri flows into the third runner R _2D and then is split into each gate GA and GB, as in the first embodiment.
Since the inner diameter of each second runner Ri is 2×rC (<2×rD), the resistance of the flow passage cross section of each second runner Ri is larger than the resistance of the flow passage cross section of the first runner R _2B .
By appropriately changing the number of second runners Ri, the arrangement pitch, and the size of rC, the flow passage resistance of the second runner R _{22C as a} whole is made equal to that of the second runner R _2C in the first embodiment. Is possible.
As a result, as in the first embodiment, the arrival times of the injection resin M from the openings 2b to the gates GA and GB are equalized.

According to the injection molding die 11 of the present embodiment, as in the first embodiment, the injection resin can be evenly distributed to a plurality of gates, and the size can be reduced.
In particular, since the arrival time can be adjusted by appropriately changing the number of second runners Ri, the arrangement pitch, and the size of rC, it is easy to manufacture and modify the first slide core 11A.
Although the example in which rC is constant has been described above, the size of rC of each second runner Ri may be changed depending on the arrangement position of each second runner Ri in the Z direction. In this case, the arrival times can be more easily equalized by appropriately changing the size of each of the second runners Ri, in addition to the number and arrangement pitch of the second runners Ri. In particular, if the size of the flow passage cross section of each second runner Ri is increased from the central portion of the second runner R _{22C in} the Z direction toward both end portions, the second runner Ri is provided in the same manner as in the second embodiment. It is also possible to reduce the arrangement space of the runner R _{22C in} the X direction.

[Fourth Embodiment]
An injection molding die according to the fourth embodiment of the present invention will be described.
FIG. 8 is a schematic front view showing an example of a main part of an injection molding die according to the fourth embodiment of the present invention. FIG. 9 is a sectional view taken along line CC of FIG.

The injection molding die 31 of the present embodiment, the main part of which is shown in FIGS. 8 and 9, manufactures a molded product 54 (see FIG. 2) similar to that of the first embodiment.
The injection molding die 31 has a first slide core 31A and a second slide core 31B (see FIG. 9) instead of the first slide core 1A and the second slide core 1B in the injection molding die 1 of the first embodiment. Equipped with.
As shown in FIG. 8, the first slide core 31A includes a first resin flow path portion P31 instead of the first resin flow path portion P1 of the first slide core 1A. Although illustration is omitted, the first slide core 31A further includes a second resin flow path portion. The second resin flow path portion has a plane-symmetrical shape with a plane that passes through the central axis OA and is parallel to the YZ plane as a plane of symmetry.
Hereinafter, the points different from the first embodiment will be mainly described.

The first resin flow path portion P31 is replaced with the inlet runner groove 2A, the first runner groove 2B, and the second runner groove 2C in the first resin flow path portion P1 in place of the inlet runner groove 32A, the first runner groove 32B, and the second runner groove 32B. A runner groove 32C is provided.
The inlet runner groove 32A is a semicircular groove extending between the inlet 2a and the opening 32b. However, the opening 32b is opened at an end portion of the first runner groove 32B, which will be described later, near the injection port 2a. As a result, the flow path length of the inlet runner groove 32A is shorter than that of the inlet runner groove 2A.

The first runner groove 32B is a semicircular groove that linearly extends in a direction intersecting the Z direction in which the third runner groove 2D extends. The groove radius of the first runner groove 32B is a constant value rB, like the first runner groove 2B.
The first runner groove 32B is formed in a linear shape facing the X direction over the entire Z direction of the third runner groove 2D. The first end E1 closer to the first end face 1a at the longitudinal end of the first runner groove 32B is located at the end closer to the first end face 1a at the longitudinal end of the third runner R _2D. Face to face. Similarly, the second end E2 opposite to the first end E1 in the longitudinal direction of the first runner groove 32B is an end closer to the second end surface 1b at the longitudinal end of the third runner R _2D. Face to face.
Accordingly, the distance between the first runner groove 32B and the third runner groove 2D in the X direction is maximum at the first end E1 and minimum at the second end E2.
The inclination amount of the first runner groove 32B with respect to the Z axis is set for the purpose of changing the length of the second runner groove 32C in the X direction, which will be described later, in the Z direction.

As shown in FIG. 9, the second runner groove 32C is a recess communicating with the side surface of the first runner groove 32B facing the third runner groove 2D. The depth from the parting surface 1c in the second runner groove 2C is tC as in the first embodiment.
As shown in FIG. 9, the second runner groove 32C communicates with the first runner groove 32B over substantially the entire length of the first runner groove 32B in the extending direction. The width of the second runner groove 32C in the X direction changes in the Z direction according to the amount of inclination of the first runner groove 32B.

With such a configuration, as shown in FIG. 9, when the parting surfaces 1c of the first slide core 31A and the second slide core 31B come into contact with each other when the injection molding die 31 is closed, they face each other in the Y direction. The respective first runner grooves 32B, the respective second runner grooves 32C, and the respective third runner grooves 2D are respectively the first runner R _2B (downstream runner, first circular tubular flow path, first runner portion), the second The runner R _2C (downstream runner, second runner portion, plate-like flow path) and the third runner R _2D similar to those of the first embodiment are formed. Although not shown in FIG. 9, the inlet runner grooves 32A facing each other in the Y direction form an inlet runner R _32A (see FIG. 8, upstream runner).

The first runner R _32B is a flow path formed by a combination of the first runners R _2B facing each other in the extending direction Y. The first runner R _2B is a first circular tubular flow path having a first inner diameter of 2×rB. Each opening 2b is opened at the central portion (intermediate portion) in the extending direction of the first runner R _2B . The first runner R _2B faces the gates GA and GB with the second runner R _2C and the third runner R _2D interposed therebetween, and extends along the alignment of the gates GA and GB.

The second runner R _32C is the first runner R _32B except that the flow path length in the X direction between the first runner R _32B and the third runner R _2D is changed according to the route of the first runner R _32B . It is a plate-like flow path similar to the second runner R _2C in the embodiment.
As shown in FIG. 8, from the gate GA closest to the first end E1 (referred to as a third gate) to the gate GA closest to the second end E2 (referred to as a fourth gate), each gate GA, The length of the second runner R _32C in the facing direction (X direction) with respect to GB gradually decreases. For example, the length of the second runner R _32C facing the gates GA, GB is L11, L12, L13, L14, L15 (where L11>L12) from the third gate to the fourth gate, respectively. >L13>L14>L15).
As a result, the length of the flow path in the first runner R _32B and the second runner R _32C from the opening 32b toward the gates GA and GB becomes longer from the third gate toward the fourth gate. For example, the length of the flow path of the injection resin M from the opening 32b toward the third gate is approximately (2×rB+L11+2×rD). On the other hand, the length of the flow path of the injection resin M from the opening 32b toward the fourth gate is longer than (2×rB+L14+2×rD) and equal to or less than (2×rB+L15+2×rD). As a result, the flow path toward the fourth gate is significantly longer.
However, as in the first embodiment, each flow path of the downstream liner has a first runner R _32B having a low resistance and a high flow velocity, and a second runner R _32C having a high resistance and a low flow velocity. The combination of and makes it possible to equalize the arrival time from the opening 32b to each gate.
The lengths L11, L12, L13, L14, and L15 are set to lengths such that the arrival times of the injection resin M from the openings 32b to the gates GA and GB are equal. Each length can be determined by, for example, a flow simulation of the injection resin M.

According to the injection molding die 31, the opening 32b in the first runner R _32B is formed in the first end E1, and the length in the X direction of the second runner R _{32C in} the Z direction is corresponding to the opening 32b. , From the first end E1 to the second end E2. As a result, the arrival time of the injection resin M can be equalized, as in the case of the first embodiment in which the opening 2b is located at the center of the first runner R _2B .

According to the injection molding die 31 of the present embodiment, as in the first embodiment, the injection resin can be evenly distributed to the plurality of gates, and the size can be reduced.
Particularly, in the present embodiment, the opening 32b is formed at the first end E1 of the first runner R _32B close to the injection port 2a, so that the length of the inlet runner R _32A can be made shorter than the length of the inlet runner R _2A. .. As a result, the amount of injection resin M used is further reduced.

[Fifth Embodiment]
An injection molding die according to the fifth embodiment of the present invention will be described.
FIG. 10: is a typical front view which shows an example of the principal part of the injection mold of the 5th Embodiment of this invention.

As shown in FIG. 10, the injection molding die 41 of the present embodiment manufactures a molded product 54 (see FIG. 2) similar to that of the first embodiment.
The injection molding die 41 includes a first slide core 41A instead of the first slide core 1A in the injection molding die 1 of the first embodiment. Although illustration is omitted, the injection molding die 41 includes a second slide core having the same configuration as the first slide core 41A, instead of the second slide core 1B in the first embodiment.
The first slide core 41A includes a first resin flow path portion P41 instead of the first resin flow path portion P1 of the first slide core 1A. Although illustration is omitted, the first slide core 41A further includes a second resin flow path portion. The second resin flow path portion has a plane-symmetrical shape with a plane that passes through the central axis OA and is parallel to the YZ plane as a plane of symmetry.
Hereinafter, the points different from the first embodiment will be mainly described.

The first resin flow path portion P41 includes a second runner groove 42C instead of the second runner groove 2C and the third runner groove 2D in the first resin flow path portion P1. The second runner groove 42C includes a first groove portion 42a and a second groove portion 42b.
The first groove portion 42a is a recess similar to the second runner groove 2C. However, the length in the X direction may be the same as or different from that of the second runner groove 2C. In the first groove portion 42a, the end portion 42c in the X direction on the side opposite to the first runner groove 2B extends parallel to the central axis OA.

The second groove portion 42b is composed of three focusing grooves T1, T2, T3 whose width is reduced in the Z direction from the end portion 42c toward each of the gates GA, GB which the end portion 42c faces.
The focusing groove T1 is an isosceles top view that guides the injection resin M that passes through the range of ±W1/2 from the reference surface m to the gate GA (referred to as a first gate groove) on the reference surface m at the end 42c. It is a trapezoidal recess. The narrowed end of the focusing groove T1 in the X direction has the same width as the opening of the first gate groove and communicates with the first gate groove.
The focusing grooves T2 are trapezoidal recesses that are adjacent to both ends of the focusing groove T1 in the Z direction and are trapezoidal in plan view. The width of the end 42c of each focusing groove T2 is W2. The width-reduced end of each focusing groove T2 in the X direction has a width similar to the opening of the gate groove 3B and communicates with the gate groove 3B.
The focusing groove T3 is a trapezoidal recess that is adjacent to the focusing groove T2 in the Z direction and is connected to the end portion 42c outside the focusing groove T2 in the Z direction in a plan view. The width of the end 42c of each focusing groove T3 is W3. The narrowed end in the X direction of each focusing groove T3 has a width similar to the opening of the gate groove 3A (referred to as a second gate groove) arranged at both ends in the Z direction. Is in communication with.

The depths of the focusing grooves T1, T2, and T3 may be constant, or each may gradually change from the depth tC to the depth of each of the facing gate grooves.
The widths W1, W2 and W3 of the focusing grooves T1, T2 and T3 are set so that the arrival times of the injection resin M at the gates GA and GB are equal. For example, when the arrival time of the injection resin M is equal at the end 42c, W1, W2, and W3 are set to be equal to each other. For example, when the arrival time of the injection resin M varies at the end portion 42c, the width is set to a width that can average the arrival time.
The example shown in FIG. 10 illustrates an example in which the focusing grooves T1, T2, and T3 are arranged on the end portion 42c without a gap. However, for example, on the end portion 42c, a gap closed in the X direction may be formed between the focusing grooves T1 and T2 and between the focusing grooves T2 and T3.

With this configuration, when the parting surfaces 1c of the first slide core 21A and the second slide core (not shown) come into contact when the injection molding die 41 is closed, the second runner grooves facing each other in the Y direction. 42C forms the second runner R _42C (downstream runner, second runner portion).
The second runner R _42C includes a main body runner Ra and branch runners Rb1, Rb2, Rb3. The main body runner Ra is composed of a plate-like flow path substantially similar to the second runner groove 2C. The branch runners Rb1, Rb2, Rb3 are formed by the focusing grooves T1, T2, T3. Each branch runner Rb1, Rb2, Rb3 branches the injection resin M passing through the end 42c of the main body runner Ra into each gate GA, GB.

According to the injection molding die 41, the main body runner Ra is configured substantially the same as the second runner R _2C in the first embodiment. Therefore, the downstream runner of the present embodiment has substantially the same configuration as the branch runners Rb1, Rb2, Rb3 provided in place of the third runner R _2D of the first embodiment. The present embodiment is an example of the case where the third runner R _2D is not provided.

In this embodiment, the arrival time of the injection resin M at the end portion 42c is equalized or substantially equalized by the main body runner Ra as in the first embodiment, and the injection resin M passes through the branch runners Rb1, Rb2, and Rb3. Reach each gate GA, GB. Therefore, as for the injection resin M, the injection resin M in the range of the opening width of the branch runners Rb1, Rb2, Rb3 on the main body runner Ra side is shunted to the gates GA, GB. As a result, the injection resin M in the main body runner Ra is smoothly divided into the gates GA, GA.

According to the injection molding die 41 of the present embodiment, as in the first embodiment, the injection resin can be evenly distributed to the plurality of gates, and the size can be reduced.
In particular, in this embodiment, it is possible to adjust the arrival time, the inflow amount, etc. of the injection resin M by appropriately setting the width of the opening width of the branch runners Rb1, Rb2, Rb3 on the main body runner Ra side. ..

[Sixth Embodiment]
An injection molding die according to the sixth embodiment of the present invention will be described.
FIG. 11: is a typical front view which shows an example of the principal part of the injection mold of the 6th Embodiment of this invention.

As shown in FIG. 11, the injection mold 51 of this embodiment is a multi-cavity mold for manufacturing a plurality of molded products 64 (see the chain double-dashed line).
The outer shape of the molded product 64 is not particularly limited, like the molded product 54. Hereinafter, an example of a shape in which the molded product 64 can be formed by sliding in two directions will be described.
The injection molding die 51 includes a first slide core 51A instead of the first slide core 1A in the injection molding die 1 of the first embodiment. Although illustration is omitted, the injection molding die 51 includes a second slide core having the same configuration as the first slide core 51A, instead of the second slide core 1B in the first embodiment.
The first slide core 51A includes a resin flow path portion P51 instead of the first resin flow path portion P1 and the second resin flow path portion P2 of the first slide core 1A.
Hereinafter, the points different from the first embodiment will be mainly described.

The resin flow path portion P51 has molding surfaces 56A, 56B, 56C instead of the cylindrical portion molding surface 4a, the protrusion molding surface 4b, the flange molding surface 4c, and the gate grooves 3A, 3B in the first resin flow path portion P1. 56D and 56E (hereinafter sometimes abbreviated as “molding surfaces 56A to E”) and a gate groove 55.

The molding surfaces 56A, 56B, 56C, 56D and 56E all form the outer shape of the molded product 64. Each of the molding surfaces 56A to 56E has a shape obtained by dividing the outer shape of the molded product 64 into two in the Y direction.
The molding surfaces 56A to 56E are arranged apart from each other in the Z direction in this order from the side closer to the first end surface 1a. The molding surfaces 56A to 56E are arranged to face the third runner groove 2D.

The gate groove 55 is the same half as the gate groove 3A in the first embodiment except that it is a plurality of recesses that allow the molding surfaces 56A to 56E to communicate with the third runner groove 2D facing in the X direction. It is a circular groove.
Each gate groove 55 diverts the injection resin M flowing in the Z direction in the third runner groove 2D toward the protrusion molding surface 4b.

With such a configuration, when the parting surfaces 1c of the first slide core 41A and the second slide core (not shown) come into contact when the injection molding die 51 is closed, the molding surfaces 56A facing each other in the Y direction. Molding spaces SA, SB, SC, SD and SE are formed by the members E to E.
As the resin flow path, an inlet runner R _2A , a first runner R _2B , a second runner R _2C , a third runner R _2D, and a plurality of gates GC, which are similar to those in the first embodiment, are formed. It
The gate GC is formed by the respective gate grooves 55 facing each other in the Y direction.

According to the injection molding die 51, the injection resin M injected from the injection port 2a is the first runner R _2A , the first runner R _2B , the second runner R _2C , and the third runner R _2D. After flowing in the same manner as in the form, it is divided into each gate GC. The injection resin M flowing through each gate GC is filled in the molding spaces SA, SB, SC, SD, SE. As a result, five molded products 64 are manufactured.
As described above, in the injection molding die 51 of the present embodiment, the injection resin can be evenly distributed to the plurality of gates as in the first embodiment, and the size can be reduced. The present embodiment is an example in which the flow dividing destinations of the gate are the molding surfaces 56A to 56E for manufacturing the molded products 64 which are independent of each other.

In the description of the first to third, fifth, and sixth embodiments, the case where the upstream runner opens at the center of the first runner portion has been described. However, the position of the opening of the upstream runner in the first runner portion may be the middle portion of the first runner portion, and is not limited to the exact center portion in the length direction of the first runner portion. In this case, the plan view shapes of the first runner portion and the second runner portion may be asymmetric with respect to the plane passing through the opening.

In the above description of the fourth embodiment, the case where the inlet runner R _32A (upstream runner) opens vertically to the first runner R _32B (first runner portion) has been described. However, there is no problem even if the upstream runner and the first runner are connected substantially horizontally (linearly).

In the above description of the first to fourth and sixth embodiments, the example in which the downstream runner has the third runner portion has been described. However, the third runner portion may be omitted.
For example, in the first embodiment, depending on the length of the second runner R _2C in the X direction, the resin pressure after the completion of the filling of the first runner R _2B causes the resin MC to be laminarized, so that the resin MC The tip surface of the is evenly leveled. In this case, since the front end surface of the resin MC is flattened into a straight line extending in the Z direction before the filling of the second runner R _2C is completed, even if the third runner R _2D is omitted, each gate GA, The arrival time of the injection resin M to GB is equalized.

In the above description of the second embodiment, an example in which each second runner Ri has a linear shape has been described. However, a part of each second runner Ri may be awakened to a waveform having an amplitude in the Z direction. In this case, since it is possible to provide a difference in the length of each second runner Ri without increasing the bending amount of the first runner R _2B , it is easy to reduce the size. For example, the same effect can be obtained by changing the flow passage cross section of each second runner Ri and the flow passage width in the Z direction.

In the above description of the sixth embodiment, an example in which the injection molding die 51 manufactures a plurality of molded products 64 having the same shape has been described. However, by appropriately changing the shapes of the molding surfaces 56A to 56E, it is possible to manufacture a plurality of molded products having different shapes.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments. Additions, omissions, substitutions, and other changes can be made to the configuration without departing from the spirit of the present invention.
Also, the invention is not limited by the above description, but only by the appended claims.

1, 11, 21, 31, 31, 41, 51 Injection mold 1A, 11A, 21A, 31A, 41A, 51A 1st slide core 1B, 11B, 31B 2nd slide core 1c Parting surface 1C Core 1d, 54d Outer periphery Surface 2a Inlet 2b, 32b Opening 2A, 32A Inlet runner groove 2B, 32B First runner groove 2C, 12C, 32C, 42C Second runner groove 2D Third runner groove 3A, 3B, 13C, 22C, 55 Gate groove 4a Cylinder Part molding surface (molding surface)
4b Projection surface (molding surface)
4c Flange molding surface (molding surface)
54, 64 Molded product 54a Cylindrical part 54b Projection part 54c Flange part 56A, 56B, 56C, 56D, 56E Molded surface m Reference surface F1, F2 Resin flow path GA, GB, GC Gate M Injection resin O, OA, OB, OC center axis P1, P11, P21, P31, P41 First resin flow path portion P2 Second resin flow path portion P51 Resin flow path portion _R2A , _R32A Inlet runner (upstream runner)
R _2B , R _32B 1st runner (downstream runner, 1st runner part)
R _2C , R _12C , R _22C , R _32C , R _42C , Ri 2nd runner R _2D 3rd runner S, SA, SB, SC, SD, SE Molding space SL1, SL2 slit

Claims (8)

An upstream runner having an injection port through which injection resin is injected,
A molding surface for transferring the surface shape to the injection resin,
A plurality of gates opening in the molding surface,
A downstream runner that communicates with each of the upstream runner and the plurality of gates and divides the injection resin injected into the injection port into each of the plurality of gates,
Equipped with
The downstream runner is
It has an opening through which the injection resin injected into the injection port flows, and a first circular tubular flow channel having a first inner diameter, and the opening is open to the first circular tubular flow channel. A first runner portion that faces the plurality of gates and extends along an array of the plurality of gates;
The first runner portion is in communication with each of the plurality of gates, and has a flow passage cross section having a higher resistance than that of the first runner portion, so that the arrival time from the opening to each of the plurality of gates is increased. A second runner part that equalizes the
including,
Injection mold. The second runner portion includes a plate-shaped channel having a slit that opens to the first runner portion, and the size of the slit and the channel width in the thickness direction of the plate-shaped channel are the first inner diameter. Less than,
The injection mold according to claim 1. The downstream runner is
Further comprising a third runner part communicating with the second runner part and each of the plurality of gates and having a second circular tubular flow path having a flow path cross section having a resistance lower than that of the second runner part,
The injection mold according to claim 1. The opening is formed in an intermediate portion in the extending direction of the first circular tubular flow path,
The first circular tubular flow path is curved in a concave shape approaching the plurality of gates in a facing direction with respect to the plurality of gates, as the first circular tubular flow path is separated from the intermediate portion in the extending direction. ,
The injection mold according to claim 1. The opening is formed in an intermediate portion in the extending direction of the first circular tubular flow path,
The length of the second runner portion in the facing direction with respect to the plurality of gates becomes shorter as the distance from the intermediate portion in the extending direction increases,
The injection mold according to claim 1. The opening is formed in an intermediate portion in the extending direction of the first circular tubular flow path,
The size and the flow passage width are increased with increasing distance from the intermediate portion in the extending direction,
The injection mold according to claim 2. The opening is formed at a first end portion in the extending direction of the first circular tubular flow path,
In the first circular tubular flow channel, the distance between the first circular tubular flow channel and the array of the plurality of gates is from the first end portion toward the second end portion opposite to the first end portion. Are arranged to decrease,
The length of the second runner portion becomes shorter as it goes away from the first end portion in the extending direction,
The injection mold according to claim 1. An upstream runner having an injection port through which injection resin is injected,
A molding surface for transferring the surface shape to the injection resin,
A plurality of gates opening in the molding surface,
A downstream runner that communicates with each of the upstream runner and the plurality of gates and divides the injection resin injected into the injection port into each of the plurality of gates,
Equipped with
The downstream runner is
It has an opening through which the injection resin injected into the injection port flows, and a first circular tubular flow channel having a first inner diameter, and the opening is open to the first circular tubular flow channel. A first runner portion that faces the plurality of gates and extends along an array of the plurality of gates;
Each of the first runner portion and each of the plurality of gates communicates with each other, has a flow passage cross section having a higher resistance than the first runner portion, and has the shortest distance from the first runner to each of the plurality of gates. A second runner portion whose distance varies depending on the shortest distance from the opening to the plurality of gates,
including,
Injection mold.

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