JP2004188794A - Cylindrical member and injection mold for molding the member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an injection mold for molding a cylindrical member, which reduces the occurrence of a burr along the parting line (mold split line part) of an inner peripheral part. <P>SOLUTION: The injection mold has a fixed core 5 having a primary pin gate 5a, outside slide cores 4A, 4E, etc. slidable outward, inside slide cores 2C, 3A, etc. movable inward and a center core 1. Secondary sprue parts 4b and 4c communicating with the primary pin gate 5a while straddling the mold matching surface 4f of the outside slide cores and secondary gate parts 4c and 4e are provided to the outside slide cores. Since the gate opening of the secondary gate is arranged so as to be away by a prescribed distance from the parting line of the mating surface between the outside slide cores 4A and 4E, an injected high-pressure molten resin does not directly reach the parting line part to control the occurrence of the burr. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a cylindrical member whose inner and outer peripheral surfaces are injection-molded, and an injection mold for molding the cylindrical member.
[0002]
[Prior art]
According to the injection molding die using the conventional inner slide core (open core), a member having a complicated shape in which a cam, a helicoid or the like is formed on the inner peripheral surface, such as a camera frame member, can be easily formed. can do. As an injection molding die using the inner slide core described in Patent Document 1 or Patent Document 2, the first slide core and the second slide core divided into six parts are a center core. The center core is retracted in the axial direction when the mold is opened, and the first and second slide cores are constricted to the center core side to take out a molding member. ing. Such an injection mold has a feature that an article having a complicated shape can be easily formed, but there is a problem that burrs are easily generated on a divided surface of the mold.
[0003]
As a conventional method of preventing burrs, a method of increasing the mold clamping force and bringing the mold splitting surface into close contact with a larger force is generally used. As another means, there is a method disclosed in Patent Document 3. In this method, as shown in a partial sectional view of a mold in FIG. 20, one of the divided surfaces 102a of the molds 101 and 102 to be abutted against the divided surface 101a of the cavity portion 103 is provided with a convex contact surface. Accordingly, a high surface pressure is applied to prevent the occurrence of burrs. If burrs still occur in the molded product, the burrs must be removed manually.
[0004]
[Patent Document 1]
The above Patent Document 1 is Japanese Patent Publication No. Hei 1-446296.
[0005]
[Patent Document 2]
Patent Document 2 is Japanese Patent Publication No. 4-42971.
[0006]
[Patent Document 3]
Patent Document 3 is JP-A-2001-232639.
[0007]
[Problems to be solved by the invention]
According to the inner slide type (open core type) described in Patent Document 1 or 2, there is a possibility that burrs may be generated between the first slide core and the second slide core, but the mold clamping force is used. However, due to its mold structure, the adhesion between the first slide core and the second slide core does not become so large. That is, even if the mold clamping force is increased, it is not effective in preventing burrs.
[0008]
Therefore, even if an attempt is made to apply the burr generation prevention structure according to Patent Document 3 to the inner slide type, since the shapes of the first slide core and the second slide core are complicated, the convex shape shown in FIG. In order to provide a contact surface on the slide core, a high-precision processing technique is required, and application is extremely difficult. It is difficult to remove the burrs generated on the inner peripheral portion of the molded product, and it can be said that it is an inevitable requirement to suppress the generation of such burrs.
[0009]
The present invention has been made in order to solve the above-described problem, and has as one object to provide a cylindrical member having less burr on a parting line (a parting line portion) of an inner peripheral portion. Another object of the present invention is to provide an injection mold for injection molding a cylindrical member with less burrs.
[0010]
[Means for Solving the Problems]
The cylindrical member according to claim 1 of the present invention has an outer peripheral surface and an inner peripheral surface, and is formed by an injection mold having a plurality of inner slide cores for forming the inner peripheral surface. In this case, the gate mark on the outer peripheral surface is formed at least 1.5 mm or more in the circumferential direction from a parting line between the plurality of inner slide cores.
[0011]
A cylindrical member according to a second aspect of the present invention is the cylindrical member according to the first aspect, having an outer peripheral surface and an inner peripheral surface, and having a plurality of inner slide cores for forming the inner peripheral surface. A cylindrical member formed by a molding die, wherein the gate mark on the outer peripheral surface is formed at least 3 mm or more in the circumferential direction from a parting line between the plurality of inner slide cores.
[0012]
The cylindrical member according to claim 3 of the present invention is the cylindrical member according to claim 1 or 2, wherein the outer peripheral surface is formed by a plurality of outer slide cores, and the plurality of outer slide cores are aligned. It is molded by a mold provided with a gate on the surface.
[0013]
The cylindrical member according to claim 4 of the present invention is a cylindrical member formed by injection molding, wherein a center core and an inner peripheral surface of the cylindrical member are formed. A plurality of first slide cores provided relative to the center core and forming an inner peripheral surface of the cylindrical member, between the plurality of first slide cores around the center core. And has a mating surface with the first slide core. When the mold is closed, the mating surface is covered with the mating surface of the first slide core, and is configured to be diverted. It is formed by an injection molding die having a plurality of movable second slide cores and an outer shape for forming an outer peripheral surface of the cylindrical member having a gate. Sura It is between parting line formed by the-core and the second slide core, and, located at the end face neighborhood of the first outer surface of the slide core and the facing or the first slide core.
[0014]
The injection molding die according to claim 5 of the present invention is an injection molding die for molding a cylindrical member by injection molding, wherein the center core and the inner peripheral surface of the cylindrical member are formed. A plurality of first slide cores are provided around the center core and are relatively movable with respect to the center core, and the plurality of first slide cores are formed around the center core to form an inner peripheral surface of the tubular member. Are arranged between the slide cores, and have a mating surface with the first slide core. The mold is configured such that the mating surface is covered by the mating surface of the first slide core when the mold is closed, and when the mold is opened and closed. A plurality of second slide cores movable relative to the center core, and a first gate provided in a circumferential direction of an outer peripheral surface of the tubular member so as to face the first slide core, and have an outer shape. And a profile type for forming.
[0015]
The injection molding die according to claim 6 of the present invention is the injection molding die according to claim 5, further comprising: the outer molding die slides in the circumferential direction of the outer peripheral surface of the cylindrical member. A second gate is provided to face the core, and the area of the second gate opening is smaller than the area of the gate opening of the first gate.
[0016]
The injection molding die according to a seventh aspect of the present invention is the injection molding die according to the fifth aspect, wherein the outer molding die is further slid in the circumferential direction of the outer peripheral surface of the cylindrical member. A second gate is provided so as to face the core, and the cross section of the sprue leading to the second gate at right angles to the direction of travel of the injection molding material flow path is the cross section of the sprue leading to the first gate. Less than right-angle cross section.
[0017]
The injection molding die according to claim 8 of the present invention is the injection molding die according to claim 5, further comprising the second slide in the outer peripheral molding in a circumferential direction of an outer peripheral surface of the cylindrical member. A second gate is provided so as to face the core, and the length of the injection molding material flow path of the second gate is longer than the length of the injection molding material flow path of the first gate facing the first slide core. .
[0018]
An injection molding die according to a ninth aspect of the present invention is the injection molding die according to the fifth aspect, further comprising the second slide core in the outer shape in a circumferential direction of an outer peripheral surface of the cylindrical member. A second gate is provided so as to face the second gate, and the length of the injection molding material flow path of the sprue leading to the second gate is longer than the length of the injection molding material flow path of the sprue leading to the first gate.
[0019]
In the injection molding die according to claim 10 of the present invention, in an injection molding die for molding a cylindrical member by injection molding, a center core and an inner peripheral surface of the cylindrical member are formed. A plurality of first slide cores which are provided around the center core and which are relatively movable with respect to the center core, and are provided apart from each other around the center core to form an inner peripheral surface of the cylindrical member; A plurality of second slide cores disposed between the plurality of first slide cores and movable relative to the center core; and the first slide in a circumferential direction of an outer peripheral surface of the tubular member. An outer shape for forming an outer shape of an outer peripheral surface of the cylindrical member provided with a gate at a distance of 1.5 mm or more from a parting line between the core and the second slide core;
[0020]
In an injection molding die according to claim 11 of the present invention, in an injection molding die for molding a cylindrical member by injection molding, a center core and an inner peripheral surface of the cylindrical member are formed. A plurality of first slide cores which are provided around the center core and which are relatively movable with respect to the center core, and are provided apart from each other around the center core to form an inner peripheral surface of the cylindrical member; A plurality of second slide cores disposed between the plurality of first slide cores and movable relative to the center core; and the first slide in a circumferential direction of an outer peripheral surface of the tubular member. An outer shape for forming an outer shape of an outer peripheral surface of the cylindrical member provided with a gate at a distance of 3 mm or more from a parting line between the core and the second slide core;
[0021]
The injection mold according to claim 12 of the present invention is the injection mold according to claim 10 or 11, wherein a parting line portion between the first slide core and the second slide core includes: When the mold is closed, the first slide core is disposed so as to cover the second slide core, and the gate is connected to the first slide core or the second slide core. They are arranged to face each other.
[0022]
The injection mold according to claim 13 of the present invention is the injection mold according to claim 10 or 11, wherein a parting line portion between the first slide core and the second slide core includes: When the mold is closed, the first slide core is disposed so as to cover the second slide core, and the gate is disposed so as to oppose only the first slide core. ing.
[0023]
In an injection molding die according to claim 14 of the present invention, in an injection molding die for molding a cylindrical member by injection molding, a center core and an inner peripheral surface of the cylindrical member are formed. A plurality of first slide cores are provided around the center core and are relatively movable with respect to the center core, and the plurality of first slide cores are formed around the center core to form an inner peripheral surface of the tubular member. Are arranged between the slide cores, and have a mating surface with the first slide core when the mold is closed. The mating surface is configured to be covered by the first slide core, and the center core is formed when the mold is opened and closed. And a plurality of second slide cores relatively movable with respect to each other, and in the circumferential direction of the outer peripheral surface of the cylindrical member, opposed to the vicinity of a parting line between the first slide core and the second slide core. A gate is provided so that the direction of injection of molding material from the gate relative to a straight line passing through the center core center and the parting line on a plane orthogonal to the mold opening and closing direction is equal to that of the first slide core. The gate has an outer shape for forming an outer shape of the cylindrical member having a predetermined angle toward the outer peripheral surface.
[0024]
The injection molding die according to claim 15 of the present invention is the injection molding die according to claim 14, wherein the gate is located at a predetermined distance from the parting line in a circumferential direction of an outer peripheral surface of the cylindrical member. The first slide core is spaced apart and faces the outer peripheral surface of the first slide core.
[0025]
The injection mold according to claim 16 of the present invention is the injection mold according to claim 15, wherein the predetermined angle is α, and the predetermined distance is d.
α ≧ 10 ° and d ≧ 0.5mm
It is.
[0026]
The injection mold according to claim 17 of the present invention is the injection mold according to claim 15, wherein the predetermined angle is α, and the predetermined distance is d.
α ≧ 15 ° and d ≧ 1.0mm
It is.
[0027]
The injection molding die according to claim 18 of the present invention is the injection molding die according to claim 15, wherein the external form is formed of a plurality of outer slides, and a sprue and the gate are provided on a parting surface that contacts each other. ing.
[0028]
In the injection molding die according to claim 19 of the present invention, in an injection molding die for molding a cylindrical member by injection molding, a center core and an inner peripheral surface of the cylindrical member are formed. A plurality of first slide cores are provided around the center core and are relatively movable with respect to the center core, and the plurality of first slide cores are formed around the center core to form an inner peripheral surface of the tubular member. Are arranged between the slide cores, and have a mating surface with the first slide core when the mold is closed. The mating surface is configured to be covered by the first slide core, and the center core is formed when the mold is opened and closed. A plurality of second slide cores relatively movable with respect to each other, and separated from a parting line between the first slide core and the second slide core in a circumferential direction of an outer peripheral surface of the cylindrical member. A gate is provided so as to face the vicinity, and the injection direction of the molding material from the gate is the first direction with respect to a straight line passing through the center core center and the parting line on a plane orthogonal to the mold opening / closing direction. The gate has an outer shape for forming an outer shape of the cylindrical member having a predetermined angle toward the outer peripheral surface of the slide core.
[0029]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a longitudinal sectional view of a cam frame of a tubular member according to a first embodiment of the present invention.
[0030]
The cam frame 10 of the present embodiment is, for example, a cylindrical frame member applicable to a lens barrel of a camera, and has a plurality of cam grooves 10a, 10b, 10c on an inner peripheral surface as shown in FIG. Is provided. The cam frame 1 is a synthetic resin member that can be molded by an injection molding die 9, 11, 21, 31, 41, 51, or the like of each embodiment described later. The injection molds 9 to 51 each include a divided inner slide core having a plurality of mating surfaces (parting lines) and a plurality of secondary gates / spurs (including a secondary gate portion and a secondary sprue portion). And a split outer slide core having an outer shape.
[0031]
The inner peripheral surface of the cam frame 10 is formed by the inner slide core, but a plurality of parting line traces 10d due to the mating surface at the time of molding the inner slide core remain on the inner peripheral surface. The cam groove 10a and the like are formed across the parting line trace 10d.
[0032]
The outer peripheral surface of the cam frame 10 is formed by the outer slide core. On the outer peripheral surface, a gate mark by a gate opening of a secondary gate / sprue provided on the outer slide core is formed on the parting line mark. On the other hand, it remains at a position relatively separated by a predetermined distance range in the circumferential direction. However, in the case of the cam frame 1 molded by the injection molding die 41, the gate mark remains on the end face of the cylindrical portion, not on the outer peripheral face.
[0033]
In the cam frame 10 of the present embodiment, by applying a suitable shape to the gate portion of the injection molding die 9 and the like as described later, the occurrence of burrs at the parting line portion is small and the trace of the parting line is not noticeable. It can be molded in a state. If the burr generated on the parting line portion becomes large, it becomes difficult to remove the burr. Also, if the trace of the parting line is large, a malfunction of the cam follower sliding in the cam groove 10a or the like occurs, which is not preferable. However, those problems are improved in the cam frame 10 of the present embodiment.
[0034]
Next, an injection mold according to a second embodiment of the present invention will be described with reference to FIGS.
FIG. 2 is a cross-sectional view showing a cross section (BB cross section in FIG. 3) orthogonal to the axis of the injection mold of the present embodiment. FIG. 3 is an AA cross-sectional view of FIG. 2, and FIG. 4 is an exploded perspective view of a secondary gate / sprue of the outer slide core in the injection mold. FIG. 5 is a view taken in the direction of arrow E in FIG. 3, and is a view of the secondary gate / sprue viewed from the upper sprue port side. FIG. 6 is a part of the cross section taken along line BB of FIG. 3 and shows the gate portion of the secondary gate / sprue.
[0035]
The injection molding die 9 of the present embodiment is, for example, a die capable of molding the cam frame 10 which is the cylindrical member of the first embodiment, and includes a fixed die and a movable die. As shown in FIGS. 2 and 3, the fixed type has a fixed-side core 5, and the movable type is a movable-side insert 6, a six-part inner slide type to be described later, and an external type described later. And an outer slide type.
[0036]
The six-segment inner slide die has one center core 1 movable in the direction of the axis C0 of the mold, and is disposed around the center core 1, and can slide in the radial direction with respect to the axis C0 to relatively move. It has a plurality of first slide cores 2A, 2B, 2C, which are inner slide cores, and a plurality of second slide cores 3A, 3B, 3C. The first slide core and the second slide core can slide relative to the center core 1 also in the direction of the axis C0. These relative movements occur when the mold is opened and closed.
[0037]
The center core 1 has three dovetail grooves 1a and 1b inclined at a predetermined angle with respect to the axis C0.
[0038]
Each of the first slide cores 2A has an arcuate cross-sectional shape, and has a divided outer peripheral surface 2a for forming an inner peripheral surface of the cam frame, and a mating surface 2c on both width sides of the divided outer peripheral surface 2a. And a dovetail portion 2b slidably fitted in the dovetail groove portion of the center core 1.
[0039]
Each of the second slide cores 3A has a substantially trapezoidal cross-sectional shape, and has a divided outer peripheral surface 3a for forming an inner peripheral surface of the cam frame, and the mating surface 2c inward from both ends of the divided outer peripheral surface 3a. And a dovetail portion 3b slidably fitted into the dovetail portion of the center core 1.
[0040]
The first slide cores 2A,... And the second slide cores 3A,... Are in a state where the respective mating surfaces 2c and 3c are mated, that is, in a state where the mating surface 3c is covered by the mating surface 2c. It is arranged alternately around. When the mold is in a closed state, the first slide cores 2A,... And the second slide cores 3A,. In this state, the mating surface 2c is held in a state of being in close contact with the mating surface 3c. In the mold closed state, the outer peripheral surface of the inner slide core is formed by the divided outer peripheral surfaces 2a and 3a, and the outer peripheral surface becomes the inner peripheral surface of the cavity 7 for forming the inner peripheral surface of the cam frame 10. Further, the peripheral end portions of the mating surfaces 2c and 3c serve as parting lines during molding. A parting line mark 10d on the outer peripheral surface of the cam frame 10, which is a molded product, is formed at the parting line.
[0041]
On the other hand, when opening the mold, the center core 1 moves in the mold opening direction (downward in FIG. 3) along the direction of the axis C0, so that the dovetail grooves 1a, 1b slide along the dovetails 2b, 3b. The first slide cores 2A,... And the second slide cores 3A,. During this movement, the movement amount of the second slide cores 3A,... Is larger than the movement amount of the first slide cores 2A,. The cam frame 10 molded in this mold open state can be removed from the mold.
[0042]
The outer slide type has outer slide cores 4A, 4B, 4C, 4D, 4E, and 4F divided into six parts, each of which is located outside the first and second slide cores in the radial direction of the axis C0. Can be slid outwardly.
[0043]
Each of the outer slide cores 4A,..., 4F has a divided inner peripheral surface that forms an inner peripheral surface 4a of the outer slide core. A mold mating surface 4f where the slide cores are in close contact with each other is provided. In the case of the adjacent outer slide cores, for example, the outer slide cores 4A and 4B, the mold-matching surface 4f is a division surface along a bisecting angle of an angle between the sliding directions D1 and D2, and has an axis C0. , Or the first slide core 2A,... Or the second slide core 3A,.
[0044]
In the closed state of the outer slides 4A,..., 4F, the two mold mating surfaces 4f are held in close contact with each other, and the inner peripheral surface 4a becomes the outer diameter surface of the cavity 7. The outer peripheral surface of the cam frame 10 can be formed by this outer diameter surface.
[0045]
Pin gates 5a (six places) serving as primary gates of the fixed-side core 5 are arranged on the end face on the upper surface side in FIG. 3 of the molding surface 4f of the outer slide cores 4A,. A secondary gate / sprue is arranged at each position on the mold matching surface 4f facing the pin gate 5a.
[0046]
The secondary gate / sprue includes two types of secondary gates, a first secondary gate / sprue and a second secondary gate / sprue. The first secondary gate / sprue comprises a secondary sprue portion 4b and a secondary gate portion 4c which are relatively long with respect to the second secondary gate / sprue. The second secondary gate / sprue includes a secondary sprue portion 4d and a secondary gate portion 4e which are relatively short with respect to the first secondary gate / sprue (FIG. 3). Each of the gates / sprue is provided in a symmetrical state where the gate / sprue is divided into two parts over both the molding surfaces 4f of the outer slide cores 4A,..., 4F. Then, the first secondary gate / sprue and the second secondary gate / sprue are alternately arranged on the mold matching surface 4f (FIG. 2).
[0047]
The secondary sprue portion 4b of the first secondary gate / sprue is opened at a position facing the pin gate 5a in a mold closed state, provided along a direction parallel to the axis C0, and has a length L1. The secondary sprue portion 4b has parallel wall surfaces 4bb along the sliding directions D1 and D2 so that the outer slide core can slide outward (FIGS. 3, 4, and 5). However, the parallel wall surface 4bb is not limited to the parallel surface, but may be any inclined surface that can be cut out.
[0048]
The secondary gate portion 4c of the first secondary gate / sprue communicates with the tip of the secondary sprue portion 4b and opens on the inner peripheral surface 4a of the outer slide core. That is, it has a gate opening 4cc that opens to the cavity 7 side. The circumferential position of the gate opening 4cc is desirably a position passing near the center line of the width of the second slide cores 3A,..., But need not necessarily be a position passing near the center line of the width. , 3c as long as a predetermined distance d1 (described later) is secured. The position of the gate opening 4cc in the direction of the axis C0 is a position below the fixed core 5 by a distance L1 in FIG.
[0049]
On the other hand, the secondary sprue portion 4d of the second secondary gate / sprue has a length L2 shorter than the length L1 (FIG. 3), and the other portions have the same shape as the secondary sprue portion 4b. And
[0050]
The secondary gate portion 4e of the second secondary gate / sprue is likewise provided to be open to the inner peripheral surface 4a, communicating with the tip of the secondary sprue portion 4d and having a gate opening 4ee. I have. The circumferential position of the gate opening 4ee is preferably a position passing through the center line of the width of the first slide cores 2A,..., But does not necessarily need to be a position passing near the center line of the width. It is sufficient that a predetermined distance d2 (described later) from the point 3c is secured. The position of the gate opening 4ee in the direction of the axis C0 is a position below the fixed core 5 by a distance L2 in FIG.
[0051]
In the injection molding die 9 of the present embodiment, the positions of the gate openings 4cc and 4ee of the secondary gates 4c and 4e of the secondary gate / sprue are determined by the first slide cores 2A,. One important point is that the parts are separated from the parting line positions at the ends of the mating surfaces 2c and 3c by the predetermined distances d1 and d2.
[0052]
That is, as the distances d1 and d2 along the circumferential direction between the gate openings 4cc and 4ee and the parting line in the mold 9 of the present embodiment (FIG. 6), the high-pressure molten resin is directly applied to the parting line. At least 1.5 mm, and more preferably, 3.0 mm or more should be secured even at the shortest distance so as not to hit the target. The separation distance data is data obtained by experimentally molding a cylindrical member using an injection mold. In the case of the present embodiment, as described above, the gate openings 4cc, 4ee are arranged on the center line extension of the width of the second slide cores 3A,... Or the first slide cores 2A,. The distance d is satisfied. However, the position of the gate opening is not limited to the extension of the center line of the width as described above, and in some cases, the distances d1 and d2 may be ensured.
[0053]
Gate marks are formed at the positions of the gate openings 4cc and 4ee, such as the outer slide cores 4A,... On the outer peripheral surface of the cam frame 10, which is a molded product.
[0054]
In other words, the injection mold of the present invention is provided around the center core 1 so as to be separated from each other to form the inner peripheral surface of the center core 1 and the cylindrical member. In order to form a plurality of possible first slide cores 2A, 2B, 2C and the inner peripheral surface of the cylindrical member, the plurality of first slide cores 2A, 2B, 2C are formed around the center core 1. The first slide cores 2A, 2B, and 2C are provided between the first slide cores 2A, 2B, and 2C, and the first slide cores 2A, 2B, and 2C are covered with the first slide cores 2A, 2B, and 2C when the mold is closed. A plurality of second slide cores 3A, 3B, 3C that can move relative to the center core 1 when the mold is opened and closed, and a gate 4e that faces at least the first slide cores 2A, 2B, 2C. It may always be as having a a contour mold for forming the outer shape.
[0055]
Next, an operation when the cam frame 10 is molded by the injection molding die 9 of the present embodiment having the above-described configuration will be described.
First, the injection mold 9 is set in a closed state. That is, as shown in the figure, when the outer slide cores 4A,..., 4F are slid below the fixed core 5 to bring the mold mating surfaces 4f into contact with each other, the inner slide core 4A The outer peripheral surface of the cavity 7 (the outer peripheral surface of the cam frame 10) is formed by the peripheral surface 4a. On the other hand, by moving the center core 1 upward, the first slide cores 2A, 2B, 2C and the second slide cores 3A, 3B, 3C are slid to predetermined outside positions. In the sliding state, the mating surfaces 2c and 3c of the first and second slide cores are held in a contact state. The inner peripheral surface of the cavity 7 (the inner peripheral surface of the cam frame 10) is formed by the divided inner peripheral surfaces 2a and 3a of the first and second slide cores. The upper end face of the cavity 7 in the figure is formed by the fixed core 5, and the lower end face in the figure is formed by the movable insert 6 and the steps of the first and second slide cores.
[0056]
Under the mold closed state, a high-pressure molten resin is injected from the pin gate 5a into the secondary sprue portions 4b and 4d of the first and second secondary gates / sprue. The molten resin is injected into the cavity 7 from the secondary gates 4c and 4e.
[0057]
After the molten resin is cooled and solidified, the mold 9 is opened. That is, the outer slide cores 4A,..., 4F are slid in the directions D1, D2 and the like to be opened. At the same time, by moving the center core 1 downward in the direction of the axis C0, the first slide cores 2A,... And the second slide cores 3A,. The molded product of the frame 10 can be taken out of the mold 9.
[0058]
As described above, in the injection molding die 9 of the present embodiment, the gate openings 4cc and 4ee are separated from the parting line positions at the ends of the mating surfaces 2c and 3c by the separation distances d1 and d2. The molten resin injected into the cavity 7 at high pressure and high speed from the gate opening does not directly reach the parting line from the gate. Therefore, burrs hardly occur at the parting line portions (the end portions of the mating surfaces 2c and 3c).
[0059]
Furthermore, in the injection molding die 9 of the present embodiment, the secondary sprue portions 4b, 4d and the secondary gate portions 4c, 4e of the secondary gate / sprue are attached to both the mold mating surfaces 4f of the outer slide cores 4A,. Since the secondary gate portion is provided in a state of being divided into a symmetrical shape, it is easy to cut out the secondary gate portion.
[0060]
In addition, in the injection molding die 9 of the present embodiment, two types of secondary gates / spurs having different sprue lengths are alternately arranged around the cavity 7 as secondary gates / spurs. The molten resin is injected into the cavity 7 in a more uniform state, and the moldability is improved.
[0061]
Although the injection molding die 9 of the present embodiment has been described for molding the cam frame 10 as a cylindrical member, the present invention is not limited to this, and other shapes of cylindrical molding molded by applying the divided inner slide core are applicable. The same configuration can be applied to a molding die for a member.
[0062]
Next, an injection mold according to a third embodiment of the present invention will be described with reference to the cross-sectional view of the mold shown in FIG.
The injection molding die 11 of the present embodiment is characterized in that secondary gates / spurs are provided at three locations on a six-part outer slide core as shown in FIG. In addition, the fixed-side core 5 on which the pin gate 5a is arranged and the six-split inner slide type to which the first and second slide cores 2A,. It is the same as the case, the same reference numerals are given, and different portions will be described below. The cylindrical member to be formed is, for example, the cam frame 10 of the first embodiment.
[0063]
In the injection molding die 11 of the present embodiment, three sets of identically shaped secondary gates / sprues are arranged across the outer slide cores 14A and 14F, 14B and 14C, and 14f and 14E. .
[0064]
The three sets of secondary gates / sprues each have a secondary sprue portion 14b having an opening facing the pin gate 5a, and a gate opening 14cc communicating with the secondary sprue portion and opening on the inner peripheral surface 14a of the outer slide core. And a secondary gate portion 14c having
[0065]
The secondary sprue part 14b and the secondary gate part 14c have the same shape as the secondary sprue part 4b and the secondary gate part 4c of the secondary gate / sprue in the first embodiment. The mold mating surface 14f of the outer slide core on which the secondary sprue portion 14b and the secondary gate portion 14c are arranged is located on a radial line connecting the axis C0 and the width center of the first slide cores 2A, 2B, 2C. are doing. Therefore, the gate opening 14cc of the secondary gate portion 14c is located in the widthwise middle of the mating surfaces 2c, 3c of the first and second slide cores outside the first slide cores 2A,. However, the gate opening may be disposed at a position where the circumferential separation distance from the ends of the mating surfaces 2c and 3c is, for example, 1.5 mm or more, and more desirably 3 mm or more. It is not limited to the middle position in the width direction,
When the cam frame 10 is formed by the injection mold 11 having the above-described configuration, the mold is closed as in the case of the injection mold 9 of the second embodiment. Under the mold closed state, a high-pressure molten resin is injected from the pin gate 5a into the secondary sprue portion 14b of the secondary gate / sprue. The molten resin is injected into the cavity 17 from the secondary gate 14c.
[0066]
After the molten resin is cooled and solidified, the mold 11 is opened. That is, the outer slide cores 14A,..., 14F are slid in the directions D1, D2 and the like to be opened. At the same time, by moving the center core 1 downward in the direction of the axis C0 in the drawing, the first slide cores 2A,... And the second slide cores 3A,. The molded product of the formed cam frame 10 can be taken out of the mold 11.
[0067]
In the case of the injection molding die 11 of the present embodiment, when the molten resin is injected, the first slide core 2A on the side of the mating surface 2c abutting so as to cover the outside of the mating surface 3c of the second slide cores 3A,. Are pressed by the high pressure and high radiation power of the molten resin acting on the gate opening. On the other hand, since there is no gate opening outside the second slide cores 3A,..., The high pressure of the molten resin does not directly act. Therefore, a state is obtained in which the mating surface 2c is strongly adhered to the mating surface 3c. Further, since the gate opening is located at a predetermined distance from the end of the mating surface 2c and the end of the mating surface 3c, the molten resin does not flow directly from the gate to the end of the mating surface 2c and the end of the mating surface 3c. . Therefore, the occurrence of burrs at the parting line portions at the ends of the mating surfaces 2c and 3c is suppressed.
[0068]
Next, an injection mold according to a fourth embodiment of the present invention will be described with reference to FIGS.
FIG. 8 shows a cross-sectional view (NN section in FIG. 9) of the injection molding die of the present embodiment. FIG. 9 is a sectional view taken along line MM of FIG.
[0069]
In the injection molding die 9 of the second embodiment, two types of secondary gates / spurs having different sprue lengths are arranged at respective positions on the mold mating surface 4f of the outer slide core. (FIG. 3). On the other hand, in the injection molding die 21 of the present embodiment, two types of secondary gates / sples are also provided. The flow path cross-sectional area of the secondary sprue portion through which the molten resin flows, and the flow path of the secondary sprue portion In addition, two types of secondary gates / spurs having different lengths, secondary gate lengths, and gate opening areas are provided. The other mold structures, that is, the six-part inner slide mold and the outer slide mold are applied, and the configuration is the same as that of the injection mold of the second embodiment. Therefore, the same components are denoted by the same reference numerals, and description thereof will not be provided. Differences will be described below.
[0070]
The injection molding die 21 of the present embodiment is, for example, a die capable of molding the cam frame 10 which is the cylindrical member of the first embodiment, and includes a fixed die and a movable die. As shown in FIGS. 8 and 9, the fixed type has a fixed-side core 5, and the movable type includes a movable-side insert 6, a center core 1 that forms a six-part inner slide type, and a first core. , 2C and second slide cores 3A,..., 3C, and outer slide cores 24A,.
[0071]
As shown in FIGS. 8 and 9, pin gates 5a (six places) serving as primary gates of the fixed-side core 5 are arranged on the upper surface side of the mold matching surface 24f of the outer slide cores 24A,. I have. A secondary gate / sprue is arranged at each position on the mold matching surface 24f facing the pin gate 5a.
[0072]
The secondary gate / sprue includes two types of gates, a first secondary gate / sprue and a second secondary gate / sprue. The first secondary gate / sprue has a wider cross-sectional area at right angles to the sprue length L3 as compared with a second secondary gate / sprue described later as a shape relating to the molten resin flow path. It has a secondary sprue portion 24b and a secondary gate portion 24c having a relatively short flow path length and a gate opening 24cc having a relatively large opening area.
[0073]
On the other hand, the second secondary gate / sprue has a sprue length L3 at the first secondary gate / sprue as a shape relating to the molten resin flow path, and a longer sprue length relative to the flow path cross-sectional area. L4 and a secondary sprue portion 24d having a narrower flow path cross-sectional area and a gate opening 24ee having an area longer than the gate flow path length of the first secondary gate / sprue and smaller than the gate opening area. And a secondary gate 24e.
[0074]
Each of the first and second secondary gates / sprue is provided in a symmetrical state in which each of the outer slide cores 24A,. On the other hand, the first secondary gate / sprue and the second secondary gate / sprue are alternately arranged (FIG. 8). In addition, the opening area of the pin gate 5a facing the first and second secondary gates / spurs is also the same as that of the second secondary gate / sprue on the side of the secondary sprue portion 24d. The sprue is smaller than that on the secondary sprue portion 24b side.
[0075]
The secondary sprue portions 24b and 24d of the first and second secondary gates / sprues are opened at positions facing the pin gate 5a in a mold closed state, and are provided along a direction parallel to the axis C0. The secondary sprues 24b and 24d have wall surfaces along the sliding directions D1 and D2 so that the outer slide core can slide outward.
[0076]
The secondary gate portions 24c and 24e of the first and second secondary gates / sprues communicate with the tip of the secondary sprue portion 24b or 24d, and open to the inner peripheral surface 24a of the outer slide core. I have. Specifically, the circumferential position of the gate opening 24cc of the first secondary gate 24c on the first secondary gate / sprue side opening into the cavity 27 is located at an outer position passing through the width center line of the first slide cores 2A,. Alternatively, as shown in FIG. 8, the minimum distance along the circumferential direction between the gate opening 24 cc and the parting line portion is 1 at the shortest distance as in the second embodiment. 5 mm or more, more preferably, 3.0 mm or more is secured. The position of the gate opening 24cc in the direction of the axis C0 is located below the fixed core 5 by a distance L3 in the figure.
[0077]
On the other hand, the circumferential position of the gate opening 24ee of the secondary gate portion 24e of the second secondary gate / sprue opening into the cavity 27 is the outer position passing through the center line of the second slide cores 3A,. Although it is a position in the vicinity thereof (FIG. 8), the minimum distance along the circumferential direction between the gate opening 24ee and the parting line portion is 1.5 mm or more at the shortest distance as in the case of the second embodiment. Further, it is desirable to secure 3.0 mm or more. The position of the gate opening 24ee in the direction of the axis C0 is located below the fixed core 5 by a distance L4 in the figure.
[0078]
Next, the operation at the time of molding the cam frame 10 by the injection molding die 21 of the present embodiment having the above-described configuration is the same as that of the injection molding die 9 of the second embodiment. Originally, the high-pressure molten resin is injected from the pin gate 5a through the secondary sprues 24b and 24d into the cavity 27 from the secondary gates 24c and 24e.
[0079]
After the molten resin is cooled and solidified, the mold 21 is opened. That is, the outer slide cores 24A,..., 24F are slid in the directions D1, D2 and the like to be opened. At the same time, by moving the center core 1 downward in the direction of the axis C0, the first slide cores 2A,... And the second slide cores 3A,. The formed molded product of the cam frame 10 can be taken out of the mold 21.
[0080]
As described above, by arranging the gate openings 24cc and 24ee on the mold by a predetermined distance along the circumferential direction from the parting line portion, the gate openings 24cc and 24ee can be introduced into the cavity 27 from the gate openings at high pressure and at high speed. The injected molten resin does not directly reach the parting line from the gate. Therefore, burrs hardly occur at the parting line portions (the end portions of the mating surfaces 2c and 3c).
[0081]
Further, in the injection molding die 21 of the present embodiment, as described above, the first secondary gate / sprue and the second secondary gate / sprue correspond to the cross-sectional area of the flow path of the secondary sprue portion. And the flow path resistance (including the effect of the gate opening) of the molten resin passing through the gate / sprue is smaller on the first secondary gate / sprue side and the second secondary The gate / sprue side is large. Therefore, the first slide cores 2A,... Having the first secondary gate / sprue side gate opening 24cc located outside the cavity, have the second secondary gate / sprue side gate opening 24ee outside the cavity. Are pressed more strongly by the high pressure and high radiant power of the molten resin than the second slide cores 3A,. By pressing the first slide cores 2A,... More strongly, the mating surfaces 2c, 3c of the first and second slide cores are strongly adhered to each other when the molten resin is injected, and the ends of the mating surfaces 2c, 3c are brought close. Burrs generated in the parting line portion of the portion are suppressed.
[0082]
In the injection molding die 21 of the present embodiment, the secondary mold is formed in order to make the flow resistance (including the influence of the gate opening) different between the first secondary gate / sprue and the second secondary gate / sprue. The cross-sectional area of the sprue, the length of the secondary sprue, the length of the secondary gate, and the secondary gate opening are all different. However, the present invention is not limited to this, and at least one of the above items is selected to determine the difference. The same effect can be obtained even if the first and second secondary gates / spurs are formed so as to be attached.
[0083]
Next, an injection mold according to a fifth embodiment of the present invention will be described with reference to FIGS.
FIG. 10 is a transverse sectional view (GG sectional view of FIG. 11) of the injection mold according to the present embodiment. FIG. 11 is a sectional view taken along line FF of FIG. FIG. 12 is an exploded perspective view of a secondary gate / sprue of the injection mold. FIG. 13 is a part of a section taken along line GG of FIG. 11 and shows a section of a secondary gate portion of the secondary gate / sprue.
[0084]
The injection molding die 31 of the fifth embodiment is different from the injection molding die 9 of the second embodiment in that the first slide cores 2A,. This is a mold that is applied when it is not possible to dispose the mold mating surface of the outer slide core at a place other than the mating surface of the slide cores 3A,. This is a mold in which the mold mating surface of the outer slide core is located near the mating surface of the slide cores 3A,. Therefore, the shape of the secondary gate / sprue is different from that of the second embodiment. The other mold structures, that is, the six-part inner slide mold and the outer slide mold are applied, and the configuration is the same as that of the injection mold of the second embodiment. Therefore, the same components are denoted by the same reference numerals, and different points will be described below.
[0085]
The injection mold 31 of the present embodiment is, for example, a mold capable of molding the cam frame 10 which is the cylindrical member of the first embodiment, and includes a fixed mold and a movable mold. As shown in FIGS. 10 and 11, the fixed type has a fixed side core 5, and the movable type includes a movable side insert 6 and a center core 1, a first split type that forms a six-part inner slide type. , 2C and second slide cores 3A,..., 3C, and outer slide types 34A,. 34F of the outer slide dies 34A,..., 34F are located near the ends of the mating surfaces 2c, 3c of the first slide cores 2A,.
[0086]
As shown in FIGS. 10 and 11, pin gates 5a (six places) serving as primary gates of the fixed-side core 5 are arranged on the upper surface side of the molding surface 34f of the outer slide cores 34A,. I have. A secondary gate / sprue is arranged at each position on the mold matching surface 34f facing the pin gate 5a.
[0087]
The secondary gate / sprue is composed of a secondary sprue portion 34b and a secondary gate portion 34c, and is disposed so as to straddle the molding surface 34f of each of the outer slide cores 34A,. , 34E are provided with the secondary gate portions 34c symmetrical in the circumferential direction, and the outer slide cores 34B, 34D, 34F are provided with the secondary sprue portions 34b (FIG. 10).
[0088]
The shapes of the secondary sprue portion 34b and the secondary gate portion 34c will be described with reference to an example in which the secondary sprue portion 34b and the secondary gate portion 34c are provided on the mold matching surfaces 34f of the outer slide cores 34A and 34B. The shapes of the secondary sprue portions 34b and the secondary gate portions 34c provided on the respective mating surfaces 34f of the outer slide cores 34B and 34C, 34C and 34D, 34D and 34E, 34E and 34F, 34F and 34A are also the same. It has the shape of However, they are either the secondary gate portion 34c or the secondary sprue portion 34b symmetrical with respect to each outer slide core.
[0089]
As shown in FIG. 12, the secondary sprue portion 34b has a flow path parallel to the axis C0 from the upper surface of the outer slide core 34B, and has a surface 34bb parallel to the sliding direction D2 of the outer slide core 34B. I have. However, the parallel surface 34bb is not limited to the parallel surface, and may be any surface that can be die-cut.
[0090]
The secondary gate portion 34c is formed by an inclined surface 34ca inclined at a predetermined angle at a position facing the bottom of the secondary sprue portion 34b on the die mating surface of the outer slide core 34A. It has a gate opening 34cc that opens on the inner peripheral surface (outer surface of the cavity 27). The injection direction of the molten resin is determined by the inclined surface 34ca of the secondary gate portion 34c.
[0091]
The secondary sprue portion 34b and the secondary gate portion 34c have a predetermined positional relationship with respect to the first and second inner slide cores 2A and 3A when the outer slide cores 34A and 34B are clamped. In other words, as shown in FIG. 13, the circumferential position of the gate opening 34cc is the width of the first slide core 2A from the ends (parting line portions) of the mating surfaces 2c and 3c of the first and second slide cores 2A and 3A. A position where a predetermined separation distance d3 is secured toward the center. The inclination of the inclined surface 34ca that gives the resin injection direction is determined by the first slide core in the resin injection direction with respect to the center line connecting the axis C0 and the end surfaces 2c and 3c of the first and second slide cores 2A and 3A. A predetermined inclination angle α3 inclined to fall to the outer peripheral side of 2A is secured.
[0092]
In the injection mold 31 of the present embodiment, the distance d3 between the gate opening 34cc of the secondary gate / sprue secondary gate 34c is at least d3 .gtoreq.0.5 mm, and the slope 34ca of the gate opening 34c is The inclination angle α3, which is the inclination, is set to α3 ≧ 10 °. Further, it is desirable to adopt d3 ≧ 1.0 mm and α3 ≧ 15 °. Note that these values are values obtained by experimental examination.
[0093]
Next, the operation at the time of molding the cam frame 10 by the injection molding die 31 of the present embodiment having the above-described configuration is performed in the closed state similarly to the case of the injection molding die 9 of the second embodiment. Then, high-pressure molten resin is injected from the pin gate 5a into the secondary sprue portion 34b of the secondary gate / sprue. The molten resin is injected into the cavity 37 from the secondary gate 34c. At this time, the molten resin is inclined from the gate opening 34cc, which is a predetermined distance away from the mating surfaces 2c, 3c of the first and second slide cores 2A, 3A,. Injected toward the width center of the slide cores 2A,. Therefore, the high-speed and high-pressure molten resin does not directly hit the mating surfaces 2c, 3c of the first slide cores 2A,... And the second slide cores 3A,.
[0094]
After the molten resin is cooled and solidified, the mold 31 is opened. That is, the outer slide cores 34A,..., 34F are slid in the directions D1, D2 and the like to be opened. At the same time, by moving the center core 1 in the direction of the axis C0 and in the direction away from the fixed mold (downward in the figure), the first slide cores 2A,... And the second slide cores 3A,. Then, the molded product of the cam frame 10 formed in the cavity 27 can be taken out from the mold 31.
[0095]
According to the injection molding die 31 of the present embodiment, the outer slide cores are provided near the mating surfaces of the first slide cores 2A,... And the second slide cores 3A,. , And a high-speed, high-pressure molten resin is applied to the ends of the mating surfaces 2c, 3c of the first slide cores 2A,... And the second slide cores 3A,. The barrier generated at the parting line portion can be suppressed without hitting the part directly.
[0096]
Further, since the position of the opening 34cc of the secondary gate portion 34c is limited on the first slide cores 2A,..., The high-pressure radiation of the molten resin acts only on the first slide cores 2A,. , The adhesion between the mating surfaces 2c, 3c with the second slide cores 3A,... Is increased, and from this point, a barrier generated in the parting line portion is suppressed.
[0097]
Next, an injection mold according to a sixth embodiment of the present invention will be described with reference to FIGS.
FIG. 14 is a cross-sectional view (a cross-sectional view taken along the line II of FIG. 15) of the injection mold of the present embodiment. FIG. 15 is a sectional view taken along line HH of FIG. FIG. 16 is a part of a cross-sectional view taken along a line II of FIG. 15 and shows an arrangement of a pin gate of the injection molding die.
[0098]
The injection mold 41 of the present embodiment is different from the injection mold 9 of the second embodiment in that a secondary gate / sprue is not provided and a pin gate is provided at a predetermined position near the end surface of the first slide core. Are arranged to suppress the occurrence of burrs on the cylindrical member formed. The other mold structure, that is, the application of the six-part inner slide mold and the outer slide mold, and the like are the same as those of the injection mold 9 of the second embodiment. Therefore, the same components are denoted by the same reference numerals, and description thereof will not be provided. Differences will be described below.
[0099]
The injection molding die 41 of the present embodiment is, for example, a die capable of molding the cam frame 10 which is the cylindrical member of the first embodiment, and includes a fixed die and a movable die. As shown in FIGS. 14 and 15, the fixed type has a fixed side core 45. The movable type is an external type, which includes a movable side insert 6, a center core 1, first slide cores 2A,..., 2C and second slide cores 3A,. , 44F.
[0100]
The fixed side core 45 is located near the upper end surface of the first slide cores 2A, 2B, 2C and at the upper end position of the cavity 47 facing the first slide cores 2A, 2B, 2C in FIG. Three sets of two pin gates 45a and 45b each having an opening are arranged. The cavity 47 is formed by dividing the inner peripheral surface 44a of the outer slide cores 44A,..., 44F, the divided outer peripheral surface 2a of the first slide cores 2A, 2B, 2C, and the second slide cores 3A, 3B, 3C. It is formed with the outer peripheral surface 3a.
[0101]
As shown in FIG. 16, the circumferential positions of the pin gates 45a, 45b are from the mating surfaces 2c, 3c of the first slide cores 2A, ... and the second slide cores 3A, ... to the pin gates 45a, 45b. The distances d4 and d5, which are circumferentially separated toward the center of the width of the first slide cores 2A, are set to 1.5 mm or more, preferably 3.0 mm or more. Note that these values are values obtained by experimental examination.
[0102]
Next, the operation at the time of molding the cam frame 10 by the injection molding die 41 of the present embodiment having the above-described configuration is performed in the closed state similarly to the case of the injection molding die 9 of the second embodiment. Then, the high-pressure molten resin is injected into the cavity 47 from the pin gate 45a. At this time, the molten resin is injected from the pin gates 45a and 45b which are separated from the mating surfaces 2c and 3c of the first and second slide cores 2A and 3A by a predetermined distance. . And the second slide cores 3A,... Do not directly hit the high-speed and high-pressure molten resin.
[0103]
After the molten resin is cooled and solidified, the mold 41 is opened. That is, the outer slide cores 44A,..., 44F are slid in the directions D1, D2 and the like to be opened. At the same time, by moving the center core 1 in the direction of the axis C0 downward in the drawing, the first slide cores 2A,... And the second slide cores 3A,. The formed product of the cam frame 10 can be taken out of the mold 41.
[0104]
According to the injection molding die 41 of the present embodiment, by arranging the pin gate on the fixed core 45 as described above, the mating surface 2c of the first slide cores 2A,... And the second slide cores 3A,. , 3c can prevent the occurrence of burrs at the parting line portion. Further, the pin gates 45a, 45b can be freely arranged without being limited by the position and size of the outer slide cores 44A,. Further, the pin gate structure of the mold 41 of the present embodiment can be adopted for a mold in which the outer slide cores 44A,... Do not exist. Further, if a large number of the pin gates are arranged on the first slide cores 2A,... Side, the molten resin injected from the pin gates generates a force for pressing the first slide cores 2A,. The adhesion between the mating surfaces 2c, 3c of the first slide cores 2A,... And the second slide cores 3A,.
[0105]
Next, an injection mold according to a seventh embodiment of the present invention will be described with reference to FIGS.
FIG. 17 shows a cross-sectional view (cross section taken along line KK of FIG. 18) of the injection mold of the present embodiment. FIG. 18 is a JJ sectional view of FIG. FIG. 19 is a cross-sectional view taken along line QQ of FIG. 18 and shows a gate opening of the submarine gate of the injection mold.
[0106]
The injection mold 51 of the present embodiment has a submarine gate provided on the outer slide core with respect to the secondary gate / sprue provided on the outer slide core such as the injection mold 9 of the second embodiment. . The structure of the injection mold 9 of the second embodiment is the same as that of the injection mold 9 of the second embodiment, for example, by applying the structure of other molds, that is, applying a 6-split inner slide mold and an outer slide mold. Therefore, the same components are denoted by the same reference numerals, and description thereof will not be provided. Differences will be described below.
[0107]
The injection molding die 51 of the present embodiment is, for example, a die capable of molding the cam frame 10 which is the cylindrical member of the first embodiment, and includes a fixed die and a movable die. As shown in FIG. 18, the fixed type has a fixed side core 55. The movable type is an outer type, including a movable side insert 6, a center core 1, first slide cores 2A,..., 2C and second slide cores 3A,. , 54F.
[0108]
The outer slide cores 54A,..., 54F each have a divided inner peripheral surface forming an outer slide core inner peripheral surface 54a, and the outer slide cores adjacent to both side surfaces of each divided inner peripheral surface are separated from each other. Is provided with a mold mating surface 54f to which is adhered. The mold matching surface 54f is formed by a divided surface of the adjacent outer slide core (FIG. 19). The mold matching surface 54f is located on a radial line connecting the axis C0 and the center of each width of the first slide cores 2A,... Or the second slide cores 3A,.
[0109]
In the closed state of the outer slides 54A,..., 54F, the two mold mating surfaces 54f are held in close contact with each other, and the divided inner peripheral surface forms the inner peripheral surface 54a. 57. The outer peripheral surface of the cam frame 10 can be formed by the outer peripheral surface.
[0110]
On the upper surface side of the molding surface 54f of the outer slide cores 54A,..., 54F in the drawing, straight-shaped secondary sprues 55a (six places) of the fixed-side core 55 are arranged. The submarine gate 54b is disposed so as to straddle each position of the mold matching surface 54f facing the sprue 55a (FIGS. 17 and 18).
[0111]
The submarine gate 54b has a flow path that is inclined from the opening of the upper surface of the mold mating surface 54f in the drawing toward the cavity 57 below the direction of the axis C0, and the cross-sectional area of the flow path is gradually reduced. A gate opening 54bb opening to the inner peripheral surface 54a is formed at the tip.
[0112]
The circumferential position of the gate opening 54bb is preferably a position passing near the width center line of the first and second slide cores 2A,..., 3A,. , The distance d6 from the mating surfaces 2c, 3c to the first slide core 2A,... Side gate opening 54bb, and the distance from the mating surfaces 2c, 3c to the second slide core 3A,. It is sufficient that a predetermined distance described later is secured as the distance d7. Further, the position of the gate opening 54bb in the direction of the axis C0 is a substantially central position below the fixed core 55 by a distance L5 in the drawing.
[0113]
The distances d6 and d7 along the circumferential direction between the gate opening 54bb and the mating surfaces 2c and 3c (parting line portions) in the mold 51 of this embodiment (FIG. 19) are at least 1.5 mm or more. Further, it is desirable to secure 3.0 mm or more.
[0114]
When the cam frame 10 is molded by the injection mold 51 of the present embodiment, high-pressure molten resin is injected into the cavity 57 at high speed from the gate opening 54bb of the submarine gate 54b. However, the gate opening 54bb of the submarine gate 54b is located at a distance d6, d7 from the mating surface 2c, 3c of the first slide core 2A,... And the second slide core 3A,. Therefore, the high-speed and high-pressure molten resin does not directly hit the mating surfaces 2c and 3c from the gate. Therefore, burrs are less likely to occur on the parting lines at the ends of the mating surfaces 2c and 3c.
[0115]
According to the injection molding die 51 of the present embodiment, the same effect as that of the injection molding die 41 of the sixth embodiment can be obtained. Further, since the gate opening 54bb at the tip of the submarine gate 54b can be arranged in the middle portion of the cavity 57, the flow balance when the molten resin is injected into the cavity 57 is improved, and the cam frame molded product to be molded is formed. Deformation due to molding can be kept small.
[0116]
In each of the embodiments described above, the six-slide inner slide type is applied, and the first slide cores 2A,... And the second slide cores 3A,. It is not limited to the mold, but may be an eight-segment mold, a ten-segment mold, a more-divided mold, or a less-divided mold.
[0117]
Further, in each of the above-described embodiments, the division number obtained by adding the number of the first slide cores and the number of the second slide cores, as the number of divisions of the outer type outer slide core, for easy understanding of the description. Although a number is employed, the invention is not limited to the number of outer slide cores. Further, the shape of each outer slide core need not be the same.
[0118]
Furthermore, in each of the above-described embodiments, an example was described in which the invention was applied to a synthetic resin injection mold, but the molding material is not necessarily limited to a synthetic resin. The gist of the present invention is applicable.
[0119]
Further, the member molded by the injection molding die of each of the above embodiments is not limited to a cylindrical member as in the case of the cam frame 10, but may be a rectangular tube or a cylindrical member composed of a cylindrical portion and a rectangular tube portion. The present invention can be applied to cylindrical members having various shapes such as members.
[0120]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, the cylindrical member which can suppress the burr which generate | occur | produces on an inner peripheral surface by arranging the gate position in an outer peripheral surface in an appropriate position in a cylindrical member can be provided. A mold capable of injection molding a member can be provided.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a cam frame of a tubular member according to a first embodiment of the present invention.
FIG. 2 is a cross-sectional view showing a cross section orthogonal to an axis of an injection mold according to a second embodiment of the present invention.
FIG. 3 is a sectional view taken along line AA of FIG. 2;
FIG. 4 is an exploded perspective view of a secondary gate / sprue of an outer slide core in the injection mold of FIG. 2;
5 is a view taken in the direction of arrow E in FIG. 3 and is a view of the secondary gate / sprue viewed from an upper entrance side.
FIG. 6 is a part of a cross-sectional view taken along the line BB of FIG. 3, showing a cross section of a secondary gate portion of the secondary gate / sprue;
FIG. 7 is a cross-sectional view of an injection mold according to a third embodiment of the present invention.
FIG. 8 is a cross-sectional view of an injection mold according to a fourth embodiment of the present invention.
FIG. 9 is a sectional view taken along line MM of FIG. 8;
FIG. 10 is a cross-sectional view of an injection mold according to a fifth embodiment of the present invention.
FIG. 11 is a sectional view taken along the line FF of FIG. 10;
FIG. 12 is an exploded perspective view of a secondary gate / sprue of the injection mold of FIG. 10;
FIG. 13 is a part of a cross section taken along a line GG of FIG. 11 and shows a cross section of a secondary gate portion of the secondary gate / sprue.
FIG. 14 is a cross-sectional view of an injection mold according to a sixth embodiment of the present invention.
FIG. 15 is a sectional view taken along line HH of FIG. 14;
FIG. 16 is a part of a cross-sectional view taken along a line II of FIG. 15 and shows an arrangement of a pin gate of the injection molding die;
FIG. 17 shows a cross-sectional view of the injection mold of the present embodiment.
FIG. 18 is a sectional view taken along the line JJ of FIG. 17;
FIG. 19 is a sectional view taken along the line QQ in FIG. 18 and shows a gate opening of a submarine gate of the injection molding die.
FIG. 20 is a sectional view around a cavity of a conventional injection mold.
[Explanation of symbols]
1… Center core
2A, 2B, 2C
... First slide core (inner slide core)
2c, 3c
… Mating surface (Mating surface part)
3A, 3B, 3C
... Second slide core (inner slide core)
4A-4F, 14A-14F, 24A-24F,
34A-34F, 44A-44F,
54A-54F
… Outer slide core (outer type)
4b, 4d, 14b, 34b
… Secondary sprue part (sprue)
4c, 4e, 14c, 34c,
... Secondary gate (gate)
4cc, 4ee, 14cc, 34cc, 54bb
… Gate opening
4f, 14f, 24f, 34f, 44f, 54f
… Mating surface
(Matching surface between outer slide cores)
9, 11, 21, 31, 41, 51
… Injection mold
10… Cam frame (tubular member)
10d ... Parting line mark
(Parting line)
24b: Secondary sprue part
(Sprue leading to the first gate)
24c... Secondary gate (first gate)
24cc… Gate opening
(Gate opening of the first gate)
24d: Secondary sprue part
(Sprue leading to the second gate)
24e... Secondary gate (second gate)
24ee ... gate opening
(Gate opening of second gate)
45a, 45b ... pin gate (gate)
54b ... Submarine gate (gate)
d1, d2, d3, d4, d5, d6, d7
… Distance (predetermined distance)
α3… inclination angle (predetermined angle)

Claims (19)

A cylindrical member formed by an injection mold having an outer peripheral surface and an inner peripheral surface, and having a plurality of inner slide cores for forming the inner peripheral surface,
A cylindrical member, wherein a gate mark on the outer peripheral surface is formed at least 1.5 mm or more in a circumferential direction from a parting line between the plurality of inner slide cores. A cylindrical member formed by an injection mold having an outer peripheral surface and an inner peripheral surface, and having a plurality of inner slide cores for forming the inner peripheral surface,
A cylindrical member, wherein a gate mark on the outer peripheral surface is formed at least 3 mm or more in a circumferential direction from a parting line between the plurality of inner slide cores. 3. The method according to claim 1, wherein the outer peripheral surface is formed by a plurality of outer slide cores, and is formed by a mold having a gate provided on a mating surface between the plurality of outer slide cores. Tubular member. In a cylindrical member formed by injection molding,
A center core, a plurality of first slide cores provided to be spaced apart from each other around the center core to form an inner peripheral surface of the cylindrical member, the first slide cores being relatively movable with respect to the center core; A plurality of first slide cores disposed around the center core to form an inner peripheral surface of the first slide core, and a mating surface with the first slide core; Is arranged so as to be covered by the mating surface of the first slide core, and further includes a plurality of second slide cores movable relative to the center core when the mold is opened and closed, and an outer periphery of the cylindrical member having a gate. Formed by an injection mold consisting of an external mold for forming the surface,
The trace of the gate is between the parting lines formed by the first slide core and the second slide core, and is opposed to the outer surface of the first slide core or the first slide core. A cylindrical member formed by injection molding, which is located near an end surface of a slide core. In an injection mold for molding a cylindrical member by injection molding,
Center core,
A plurality of first slide cores provided around the center core so as to be separated from each other and movable relative to the center core to form an inner peripheral surface of the tubular member;
In order to form the inner peripheral surface of the cylindrical member, it is disposed between the plurality of first slide cores around the center core and has a mating surface with the first slide core, and when the mold is closed, A plurality of second slide cores that are configured so that the mating surface portion is covered by the first slide core and that can move relative to the center core when the mold is opened and closed;
An outer shape for forming an outer shape in which a first gate is provided so as to face the first slide core in a circumferential direction of an outer peripheral surface of the cylindrical member;
An injection mold having: Further, a second gate is provided in the outer shape forming die so as to face the second slide core in a circumferential direction of an outer peripheral surface of the cylindrical member, and an area of the second gate opening is equal to 6. The injection mold according to claim 5, wherein the area of the first gate is smaller than the area of the gate opening. Furthermore, a second gate is provided in the outer shape forming die so as to face the second slide core in a circumferential direction of an outer peripheral surface of the cylindrical member, and injection molding of a sprue communicating with the second gate is provided. 6. The injection molding die according to claim 5, wherein a cross-sectional area perpendicular to the material flow direction is smaller than that of the sprue leading to the first gate. Further, a second gate is provided in the outer mold so as to face the second slide core in a circumferential direction of an outer peripheral surface of the cylindrical member, and an injection molding material flow path of the second gate is provided. The injection molding die according to claim 5, wherein the length is longer than the injection molding material flow path length of the first gate facing the first slide core. Further, a second gate is provided on the outer shape so as to face the second slide core in a circumferential direction of an outer peripheral surface of the tubular member, and a sprue (sprue) communicating with the second gate is provided. The injection molding die according to claim 5, wherein a material flow path length is longer than an injection molding material flow path length of the sprue leading to the first gate. In an injection mold for molding a cylindrical member by injection molding,
Center core,
A plurality of first slide cores provided around the center core so as to be separated from each other and movable relative to the center core to form an inner peripheral surface of the tubular member;
In order to form the inner peripheral surface of the tubular member, a plurality of the plurality of first slide cores are provided around the center core and are spaced apart from each other and are disposed between the plurality of first slide cores. A second slide core,
In the circumferential direction of the outer peripheral surface of the cylindrical member, an outer peripheral surface of the cylindrical member provided with a gate at a distance of 1.5 mm or more from a parting line between the first slide core and the second slide core. An outer shape for forming the outer shape;
An injection mold having: In an injection mold for molding a cylindrical member by injection molding,
Center core,
A plurality of first slide cores provided around the center core so as to be separated from each other and movable relative to the center core to form an inner peripheral surface of the tubular member;
In order to form the inner peripheral surface of the cylindrical member, a plurality of the plurality of first slide cores are provided around the center core and are spaced apart from each other and are disposed between the plurality of the first slide cores. A second slide core,
In the circumferential direction of the outer peripheral surface of the cylindrical member, the outer shape of the outer peripheral surface of the cylindrical member provided with a gate at least 3 mm away from a parting line between the first slide core and the second slide core is described. An outer shape for forming;
An injection mold having: In a parting line portion between the first slide core and the second slide core, when the mold is closed, the first slide core is disposed so as to cover the second slide core. The injection molding die according to claim 10, wherein the gate is disposed so as to face the first slide core or the second slide core. In a parting line portion between the first slide core and the second slide core, when the mold is closed, the first slide core is disposed so as to cover the second slide core. The injection mold according to claim 10 or 11, wherein the gate is disposed so as to face only the first slide core. In an injection mold for molding a cylindrical member by injection molding,
Center core,
A plurality of first slide cores provided around the center core so as to be separated from each other and movable relative to the center core to form an inner peripheral surface of the tubular member;
In order to form the inner peripheral surface of the cylindrical member, it is disposed between the plurality of first slide cores around the center core, and has a mating surface with the first slide core when the mold is closed, A plurality of second slide cores that are configured to be covered by the first slide core at the mating surface portion and that can move relative to the center core when the mold is opened and closed;
A gate is provided so as to face a parting line between the first slide core and the second slide core in a circumferential direction of an outer peripheral surface of the cylindrical member, and a plane orthogonal to the mold opening / closing direction is provided. Wherein the gate has a predetermined angle such that the injection direction of the molding material from the gate is on the outer peripheral surface of the first slide core with respect to a straight line passing through the center core center and the parting line. An outer shape for forming the outer shape of the tubular member;
An injection mold having: The gate is separated from the parting line by a predetermined distance in a circumferential direction of an outer peripheral surface of the tubular member, and faces the outer peripheral surface of the first slide core. Item 15. The injection mold according to Item 14. When the predetermined angle is α and the predetermined distance is d,
α ≧ 10 ° and d ≧ 0.5mm
The injection mold according to claim 15, wherein: When the predetermined angle is α and the predetermined distance is d,
α ≧ 15 ° and d ≧ 1.0mm
The injection mold according to claim 15, wherein: The injection molding die according to claim 15, wherein the outer shape die includes a plurality of outer slides, and a sprue and the gate are provided on a parting surface that is in contact with each other. In an injection mold for molding a cylindrical member by injection molding,
Center core,
A plurality of first slide cores provided around the center core so as to be separated from each other and movable relative to the center core to form an inner peripheral surface of the tubular member;
In order to form the inner peripheral surface of the cylindrical member, it is disposed between the plurality of first slide cores around the center core, and has a mating surface with the first slide core when the mold is closed, A plurality of second slide cores that are configured to be covered by the first slide core at the mating surface portion and that can move relative to the center core when the mold is opened and closed;
In the circumferential direction of the outer peripheral surface of the cylindrical member, a gate is provided so as to be separated from the parting line between the first slide core and the second slide core and to be opposed to the vicinity thereof, and the mold opening and closing direction is provided. The gate is at a predetermined angle with respect to a straight line passing through the center core center and the parting line in a plane orthogonal to the plane so that the injection direction of the molding material from the gate is on the outer peripheral surface of the first slide core. An outer shape for forming the outer shape of the tubular member having
An injection mold having:

Images