JP2003245949A - Valve gate type mold assembly - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the push-in quantity of a resin when a gate is closed by a valve body. <P>SOLUTION: The valve body 56 for opening and closing a gate 50 is constituted of a sleeve-like exterior body 66 and the valve pin 67 provided in the exterior body 66 in a freely slidable manner. The exterior body 66 and the valve pin 67 are respectively controlled independently and individually. When the gate 50 is closed, only the fine valve pin 67 is preceded to close the gate 50 and, thereafter, the valve pin 67 is delayed to be operated. By this constitution, the valve pin 67 goes toward the gate 50 while pushes in the resin but the push-in amount of the resin by the valve pin 67 is small because the valve pin 67 is fine. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve gate type mold apparatus used for injection molding of thermoplastic resin.

[0002]

Conventionally, in a hot runner mold apparatus for heating a resin as a molding material in a material passage to a gate to a product cavity to constantly keep a molten state, a valve pin that is a valve body is used as a gate. There is known a valve gate type mold device which is mechanically opened / closed by the method. The hot runner mold device is intended to increase the molding efficiency, and the gate is closed to prevent the resin from leaking from the gate when the mold is opened.

Here, an example of a conventional valve gate type mold device will be described with reference to FIG. 1 is a fixed die, 2 is a movable die, and these fixed die 1 and movable die 2 which are die bodies move in the vertical direction (die opening and closing direction) shown in the drawing to open and close, and when the die is closed, the product shape The product cavity 3 is formed. The fixed mold 1 has a fixed side mold plate 6 as its main body, and a fixed side mounting plate (not shown) fixed to a surface of the fixed side mold plate 6 opposite to the movable mold 2 via a spacer block. ) And a manifold 7 is provided between the fixed side mounting plate and the fixed side template 6. This manifold 7
Has a runner 8 as a material passage formed therein, and the thermoplastic resin as a molding material in the runner 8 is always kept in a molten state by heating a heater (not shown) provided in the manifold 7. It is supposed to be. The fixed-side template 6 may be composed of a plurality of members in addition to a fixed-side receiving plate or a gate bush. Further, a hole 9 is formed through the fixed-side mold plate 6, and the movable mold 2 in the hole 9 is formed.
Side tip is a gate communicating with the product cavity 3
It is 10.

Further, the fixed mold 1 is incorporated with a valve device 11 for opening and closing the gate 10. Next, the configuration of the valve device 11 will be described. In the hole 9 of the fixed-side mold plate 6, a valve body 12 whose axial direction is the mold opening / closing direction is incorporated. Most of the valve body 12 is composed of a tubular valve casing 13. One end of the valve casing 13 is a flange portion 14 and is fixed between the manifold 7 and the fixed-side mold plate 6. It is supported. At the same time, the flange portion 14 is fitted into a step portion 15 formed at the end of the hole 9 on the manifold 7 side. Further, an end portion of the outer peripheral surface of the valve casing 13 on the gate 10 side is fitted to a cylindrical fitting surface 16 formed in the hole 9. This allows
The portion of the valve casing 13 on the gate 10 side is the fixed-side template 6
Supported by. In addition, an insert 17 and a guide bush 18 are embedded and fixed to the flange portion 14 of the valve casing 13. This guide bush 18 is nested
Penetrates 17 Further, on the outer peripheral surface of the valve casing 13, a heater 21 as a heating means and a substantially cylindrical heater cover 22 that covers the heater 21 from the outer peripheral side are provided.
Are fitted. Further, the valve casing 13 is provided with a temperature sensor 23 along the inside of the heater 21.

As described above, the valve body 12 including the valve casing 13, the guide bush 18 and the heater cover 22 is in contact with the fixed-side mold plate 6 at both ends thereof, but in the other portions, Heat insulating gaps 24 and 25 are formed between the outer surface of the main body 12 and the inner surface of the hole 9. The gaps 24 and 25 are blocked by the fitting surface 16, and the gap 24 on the gate 10 side of the fitting surface 16 is a resin heat insulating layer that communicates with the gate 10 and into which the resin as the molding material flows. The gap 25 on the opposite side serves as an air heat insulating layer.

Further, a material passage 26 for communicating the runner 8 in the manifold 7 with the gate 10 is formed in the valve body 12. The material passage 26 has a substantially cylindrical shape that is positioned coaxially with the entire valve casing 13 with the mold opening / closing direction as the axial direction, and is connected and bent from the upstream end of the material passage 26, that is, the end opposite to the gate 10. The bent portion 26a that extends in communication with the bent portion 26a.
The upper part of the is communicated with the runner 8. In addition, three or more support blades 27 extending in the mold opening / closing direction are formed on the inner peripheral surface of the tip end of the material passage 26 on the gate 10 side as a valve body support portion. Further, on the gate 10 side with respect to the support blades 27, the material passage 26 has a small diameter cylindrical portion 28.
It has become.

The valve body 12 is a valve body for moving in the mold opening / closing direction to open / close the gate 10 by driving a driving device such as a cylinder device (not shown) provided on the fixed side mounting plate. A substantially columnar valve pin 31 is built in. This valve pin 31
In the above, the gate closing portion 32 formed at the tip of the gate 10 side is removably fitted into the gate 10 to close the gate 10. Further, the valve pin 31 has the die opening / closing direction as an axial direction and coaxially penetrates through the linear material passage 26, but the support blade 27 of the valve casing 13 is provided.
The outer peripheral surface is always slidably in contact with the inner edge of the. As a result, the tip of the valve pin 31 on the gate 10 side is slidably supported. The small diameter cylindrical portion 28 at the most distal end of the material passage 26 is slightly larger in diameter than the valve pin 31. Further, the valve pin 31 has the guide bush 18 at the end of the valve body 12 on the manifold 7 side.
It is supported by. That is, this guide bush
A valve pin 31 is slidably passed through the inside of 18. In addition,
In order to connect the valve pin 31 to the drive device provided on the fixed side mounting plate, the valve pin 31 also penetrates a through hole 33 formed in the manifold 7. As described above, the bent portion 26a is required in the material passage 26 in the valve body 12 because
This is because it is impossible to position the runner 8 of the manifold 7 and the material passage 26 in the valve body 12 coaxially in the mold opening / closing direction because of the valve pin 31.

Reference numeral 36 denotes a movable side mold plate of the movable mold 2. The movable side mold plate 36 forms the product cavity 3 together with the fixed side mold plate 6.

Next, the operation of the above configuration will be described. First, the fixed mold 1 and the movable mold 2 are closed, a product cavity 3 is formed between the fixed mold 1 and the movable mold 2, and then the valve pin 31 is separated from the movable mold 2 as shown by a chain line in FIG. To open the gate 10 in the direction.
Then, a molten thermoplastic resin, which is a thermoplastic molding material, is injected into the fixed mold 1 from the injection molding machine. The resin passes through the runner 8 of the manifold 7, the material passage 26 in the valve body 12, the support vanes 27 in which the valve pins 31 are fitted, and the small-diameter columnar portion 28, and then the gate 10
Flow into the product cavity 3. After the resin is filled in the product cavity 3 in this way, the pressure is maintained,
As shown by the solid line in FIG. 6, the valve pin 31 moves toward the movable mold 2 and fits into the gate 10 to close the gate 10.
Then, after the resin in the product cavity 3 is cooled and solidified, the fixed mold 1 and the movable mold 2 are opened, and the resin in the product cavity 3, that is, the molded product is taken out. After that, the mold is closed again and the above molding cycle is repeated. Throughout the entire molding cycle, the resin in the material passage 26 of the valve body 12 is constantly heated by the heater 21 like the resin in the runner 8 of the manifold 7. It is kept in the molten state.

As described above, in the valve gate type mold device, the resin in the material passage 26 is always kept in a molten state by the heating of the heater 21, and when the gate 10 is closed by the valve pin 31, the resin is kept in the material passage 26. With the resin filled, the valve pin 31 is lowered and fitted into the gate 10. Therefore, the resin filled in the material passage 26 is filled with the valve pin 31.
The resin is pushed into the product cavity 3 from the gate by the pressure received from the valve pin 31. The pressure received by this resin increases in proportion to the cross-sectional area of the valve pin 31, and in the case of a large-diameter valve pin 31 with a large cross-sectional area, the amount of resin pushed from the gate 10 toward the product cavity 3 also increases, and There was a problem of causing defective molding.

The present invention is intended to solve such a problem, and an object of the present invention is to provide a valve gate mold apparatus capable of reducing the amount of resin pushed from the gate when the gate is closed. And

[0012]

In order to achieve the above object, a valve gate type mold apparatus according to a first aspect of the present invention includes a plurality of mold bodies which are opened and closed to form a product cavity between them when the mold is closed. A valve device for opening and closing a gate for communicating a material passage provided in the mold with the product cavity, the valve device having a material passage therein and heating means for heating the material passage. In a valve gate type mold device having a valve casing, a valve body for opening and closing the gate, and a driving means for driving the valve body, the valve body is a sleeve-shaped exterior body, and an inner circumference of the exterior body is provided. And a valve pin that slides along a surface to open and close the gate, and the drive means can independently control the exterior body and the valve pin, and After closing the gate by the valve pin, which is constituted to operate to delay the outer body.

At the time of molding, a plurality of mold bodies are closed to form a product cavity between these mold bodies, a gate is opened, and a molding material is filled in the product cavity from a material passageway through the gate. Then, the valve body closes the gate. Here, the valve body is configured to slidably support the valve pin inside the exterior body, and the valve pin that opens and closes the gate is formed thin so as to have a small cross-sectional area. Then, the valve pin of the valve body is advanced, and the exterior body of the valve body is delayed and lowered while the gate is closed by the valve pin. This reduces the amount of resin pushed by the valve pin when the gate is closed.

A valve gate mold apparatus according to a second aspect of the present invention is the valve gate mold apparatus according to the first aspect of the present invention, in which a valve body supporting hole is formed through the valve casing so as to face the gate and coaxially pass therethrough. The valve body support hole is slidably supported, and the central axis of the valve body support hole and the central axis of the material passage are eccentric to bend the lower portion of the material passage. The valve body support hole is communicated with the valve body support hole.

As a result, when the molding material is filled from the material passage into the product cavity through the gate, the molding material flowing in the material passage is not blocked by the valve body, so that the fluidity of the molding material is improved.

A valve gate mold apparatus according to a third aspect of the present invention is the valve gate mold apparatus according to the second aspect, wherein the material passage is formed in the valve body supporting hole located at the end on the gate side. The lower peripheral surface is opened and communicated, and the opening is opened and closed by the exterior body.

Therefore, after closing the gate with the valve pin, the material passage for supplying the molding material is closed by the exterior body. As a result, the pressure of the resin filling the product cavity is not applied to the valve pin that closes the gate.

According to a fourth aspect of the present invention, there is provided a valve gate type mold apparatus according to the first aspect of the present invention, in which the drive means includes a cylinder body provided coaxially with each of the cylinder chambers. Each of the cylinder chambers is formed by a slidable piston, and the valve pin is fixed to one of the pistons and the exterior body is fixed to the other piston, and a through hole is provided between the pistons. A guide cylinder that slides along the through hole is formed in the one piston with a partition wall interposed, and a shaft that slides along the inner peripheral surface of the guide cylinder is formed in the other piston. It was done.

As a result, in the piston that drives the valve pin and the outer casing, the guide cylinder portion and the shaft portion formed in each piston are slidably supported with respect to each other during operation of the piston, and the inner peripheral surface of each cylinder chamber is supported. Move stably along.

According to a fifth aspect of the present invention, there is provided a valve gate type mold apparatus according to the fourth aspect of the present invention, wherein the valve gate type mold apparatus extends in a substantially cylindrical shape from a peripheral portion of a through hole formed in the partition wall. A moving guide portion is formed, and the guide cylinder portion is slidably supported by the sliding guide portion.

As a result, the contact area between the partition wall portion and the guide cylinder portion also increases, so that the operation of each piston becomes more stable.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the valve gate mold apparatus of the present invention will be described below with reference to FIGS. 41 is a fixed die, 42 is a movable die, and these fixed die 41 and movable die 42, which are die bodies, move in the vertical direction (die opening / closing direction) shown in FIG. The product cavity 43 having a product shape is formed. The fixed mold 41 has a fixed-side mold plate 46 as its main body,
The fixed-side mold plate 46 is provided with a fixed-side mounting plate (not shown) fixed via a spacer block on the surface opposite to the movable mold 42. The fixed-side mounting plate and the fixed-side mold plate are provided. A manifold 47 is provided between the manifold 47 and. In this manifold 47, a runner 48 which is a material passage is formed inside, and a thermoplastic resin which is a molding material in the runner 48 is always in a molten state by heating a heater (not shown) provided in the manifold 47. It is designed to be kept at. Incidentally, the fixed side template 46
May be composed of a plurality of members in addition to the fixed side receiving plate or the gate bush. Also,
A hole 49 is formed through the fixed-side mold plate 46, and a tip of the hole 49 on the movable mold 42 side is a gate 50 communicating with the product cavity 43.

Next, the structure of the valve device 51 incorporated in the fixed die 41 will be described. Holes in the fixed-side template 46
A valve body 52 whose axial direction is the mold opening / closing direction is incorporated in 49. Most of the valve body 52 is composed of a tubular valve casing 53, and one end of the valve casing 53 is a flange portion 54, which is fixed between the manifold 47 and the fixed side template 46. It is supported. At the same time, the flange portion 54 is fitted into the step portion 55 formed at the end portion of the hole portion 49 on the manifold 47 side. In addition, the valve body 52 has a valve body
A cylindrical valve support hole 57 for slidably supporting 56 and a material passage 58 for communicating a runner 48 in the manifold 47 with the gate 50 are formed. The valve support hole 57 is linearly formed so as to be coaxial with the gate 50 and penetrate the valve body 52. Further, the material passage 58 is eccentric with respect to the central axis of the valve support hole 57, and the bent portion 58a formed in the lower portion of the material passage 58 is opened to the lower peripheral surface of the valve support hole 57 communicating with the gate 50. As a result, the resin, which is the molding material, is bent at the bent portion 58 a
Flow into the valve support hole 57 from the
Flows into the gate 50 from. In addition, the valve casing
A heater 60, which is a heating means, and a substantially cylindrical heater cover 61 that covers the heater 60 from the outer peripheral side are fitted to the outer peripheral surface of 53, and the resin in the material passage 58 is heated by the heater 60 and melted. Kept in. Further, a short cylindrical fitting convex portion 62 is formed on the end surface of the valve casing 53 on the gate 50 side, and the outer peripheral surface of the fitting convex portion 62 is a cylindrical shape formed in the hole 49. Is fitted to the fitting surface 63 of. This allows the gate of the valve casing 53 to
The portion on the 50 side is supported by the fixed-side template 46. further,
A tapered convex portion 64 is formed so as to project from the fitting convex portion 62 to the gate 50 side. In this way, the valve body 52
Is in contact with the fixed-side template 46 at both ends thereof, but at the other portions, the outer surface of the valve body 52 and the hole 49.
Heat insulating gaps 65, 65a are formed between the inner surface and the inner surface. The gaps 65 and 65a are blocked by fitting the fitting convex portion 62 and the fitting surface 63, and the gap 65a on the gate 50 side of the fitting surface 56 communicates with the gate 50 and a molding material. Is a resin heat insulating layer into which the resin flows, and the gap 65 on the opposite side is
It becomes an air insulation layer.

The valve body 56 for opening and closing the gate 50 is slidable along a sleeve-shaped exterior body 66 slidably supported in the valve support hole 57 and the inner peripheral surface of the exterior body 66. It is constituted by a substantially columnar valve pin 67 supported by. The exterior body 66 moves in the mold opening / closing direction that is the axial direction to open / close the opening 58c of the bent portion 58a, and the valve pin 67 is positioned coaxially with the gate 50 and moves in the mold opening / closing direction that is the axial direction. It moves to open and close the gate 50. The diameter of the valve pin 67 in this embodiment is 0.
8 mm. Then, in order to drive the valve body 56, the valve body 56 penetrates the through hole 47a of the manifold 47 and is a cylinder serving as a driving means for the exterior body 66 and the valve pin 67 provided on the fixed side mounting plate 69. They are connected to the devices 70 and 71, respectively.

Next, the construction of the cylinder devices 70 and 71 will be described. The fixed side mounting plate 69 has a counterbore 74
A concave portion 75 having a cylinder body 77 of a cylinder device 70 having a substantially bottomed box shape with an open lower side in the figure and a cylinder device 71 having a cylindrical shape opening at the top and bottom are formed in the concave portion 75. The cylinder body 78 is fitted concentrically. A bottom wall portion 80 of the cylinder body 77, which serves as a partition wall, is interposed between the cylinder bodies 77 and 78, and the cylinder body 78 located on the upper side in the drawing is in contact with the bottom wall portion 80. A cylinder chamber 77a which is hermetically sealed inside by a pressing plate 81 fixed to the spot facing portion 74 in a fitted state.
Is formed. On the other hand, the cylinder body 77 located on the lower side in the drawing forms a cylinder chamber 77a sealed inside by abutting the lower surface opening against the bottom 75a of the recess 75. A piston 82 having the exterior body 66 fixed therein is slidably fitted inside one cylinder chamber 77a, and a piston 83 having the valve pin 67 fixed therein is slidably fitted inside the other cylinder chamber 78a. ing. That is, the exterior body 66 that constitutes the valve body 56 is driven by the piston 82, and the valve pin 67 can be independently controlled individually by the piston 83. In addition, the piston 82 that drives the exterior body 66 includes a divided piston body 84,
It is composed of 85. Each of these piston bodies 84, 85 is provided with a flange portion 86, 87 and a tubular guide tubular portion 88, 89 projectingly formed at the center of the flange portion 86, 87, and the guide tubular portions 88, 89 are arranged in the vertical direction. The respective flange portions 86 and 87 are superposed so as to be projected to the above, and are integrally connected by a bolt 90. Further, the piston body 85 that drives the valve pin 67 has an integral structure in which the shaft portions 92 and 93 are projected in the vertical direction from the central portion of the flange portion 91. The piston 82 that drives the exterior body 66 has the flange portions 86, 87 slidably fitted in the cylinder chamber 77a.
Guide cylinders 88 and 89 formed above and below 87 are slidably fitted in through holes 95 formed in the bottom wall 80 of the cylinder body 77 and through holes 96 formed in the bottom 75a of the recess 75, respectively. There is.
On the other hand, in the piston 83 that drives the valve pin 67, the shaft portion 92 formed on the upper surface side of the flange portion 91 is formed on the pressing plate 81 in a state where the flange portion 91 of the piston 83 is slidably fitted in the cylinder chamber 78a. The shaft portion 93 formed on the lower surface side of the flange portion 91 is slidably fitted to the through hole 97 and slides on the inner peripheral surface of the guide cylinder portion 88 formed on the upper surface side of the piston 82. It fits freely. In this way, each cylinder chamber 77
The guide cylinder 88 of the piston 82 is slidably guided in the through hole 95 of the bottom wall 80 that separates a and 78a, and the shaft 93 of the piston 83 is coaxially fitted to the inner peripheral surface of the guide cylinder 88. It is also guided. Further, the guide cylinder portion 88 and the shaft portion are provided on the periphery of the through hole 95.
A sliding guide portion 100 is formed to project so as to stably slide and guide 93, and a recess 101 for accommodating the sliding guide portion 100 is formed on the back surface side of the piston 83. Each piston 8
Cylinder chamber 77 on the outer and outer bottom surfaces of 2, 83
A packing member 102 that seals a gap is provided between a, 78a, the fixed side mounting plate 69, and the pressing plate 81.

At the upper edge of each cylinder body 77, 78, inlets 103, 104 communicating with the respective cylinder chambers 77a, 78a are formed, and further, under the cylinder body 77 for driving the exterior body 66. At the edge, its cylinder chamber 77a
An inflow port 105 that communicates with the
The cylinder chamber 78a of the cylinder body 78 on the upper side in the figure is shown at 05.
A branch passage 106 is formed to connect the inlet 105 and the inlet 105. Further, the fixed side mounting plate 69 is provided with the inflow ports 103, 1
Passages 107 and 108 communicating with 04 are formed, and a passage 109 communicating with the inflow port 105 is formed on the opposite side of the inflow ports 103 and 104.

The exterior body 66 incorporated in the piston 82
The valve pin 67 incorporated in the piston and the piston 83 is an exterior body by screws 110 and 111 screwed to the pistons 82 and 83, respectively.
66 and a large diameter head 66a formed on the upper end of the valve pin 67,
I try to hold down 77a.

Next, the operation of the above configuration will be described. First, the fixed mold 41 and the movable mold 42 are closed, and a product cavity 43 is formed between the fixed mold 41 and the movable mold 42. Then, as shown in FIG. The valve pin 67 is moved in a direction away from the movable mold 42 to open the gate 50 and the opening 58c of the material passage 58 communicating with the gate 50. Then, from the injection molding machine to the fixed mold 41
A molten thermoplastic resin, which is a thermoplastic molding material, is injected therein. This resin passes through the runner 48 of the manifold 47 and the like, and further, the material passage 58 in the valve casing 53,
It flows from the gate 50 into the product cavity 43 through the valve support hole 57 into which the valve body 56 is fitted. When the molten resin is injected, the outer cylinder body 66 and the valve pin 67 are connected to each other by the material passage 58.
Located above the opening 58c in the figure, the flow path of the molten resin is not blocked by the outer cylinder body 66 and the valve pin 67. Therefore, it smoothly flows into the product cavity 43 from the material passage 58 via the valve support hole 57 and the gate 50. After the product cavity 43 is filled with the resin in this way, it is subjected to a holding pressure, and as shown in FIG. 4, the passage 107 formed in the fixed side mounting plate 69 and the inflow port 104 of the cylinder body 71 to the cylinder body 71. By supplying air into the cylinder chamber 78a, the piston 83 moves downward in the drawing. As a result, as shown in FIG. 2A, the valve pin 67 is lowered integrally with the piston 83, the valve pin 67 is fitted into the gate 50, and the gate 50 is closed. At this time, valve pin 67
In the piston 83 that drives, the flange portion 91 of the cylinder body 71 is slidably supported on the inner peripheral surface of the cylinder chamber 78a, and the shaft portions 92 and 93 that project vertically from the center portion of the flange portion 91 are provided. The through hole 97 formed in the pressing plate 81 and the exterior body
It is slidably supported by a guide tube portion 88 of a piston 82 that drives 66. As a result, the piston 83 moves downward while maintaining a stable state. When the valve pin 67 that closes the gate 50 is moved, the outer package 66 does not move together with the valve pin 67, and the position remains fixed. And valve pin
After closing the gate 50 at 67, by supplying air from the passage 108 formed in the fixed side mounting plate 69 and the inflow port 103 of the cylinder body 70 into the cylinder chamber 77a of the cylinder body 70 as shown in FIG. The piston 82 moves downward in the figure. As a result, as shown in FIG. 2 (B), the piston
The exterior body 66 descends integrally with 82, and the material passage 58
The opening 58c is closed. Therefore, the pressure of the resin supplied from the material passage 58 is not applied to the valve pin 67 that closes the gate 50. Further, in the piston 82 that drives the exterior body 66 when the gate 50 is closed, the flange portions 86 and 87 of the cylinder body 70 are slidably supported on the inner peripheral surface of the cylinder chamber 77a, and the upper flange portion 86 The guide cylinder portion 88 protruding upward from the central portion has an outer peripheral surface slidably fitted to the inner peripheral surface of the slide guide portion 100 formed on the bottom wall portion 80, and the inner peripheral surface of the guide cylinder portion 88. Piston driving valve pin 67 on the surface
A shaft 93 of 71 is coaxially arranged in a slidably fitted state, and a guide cylinder 89 that projects downward from the center of the lower flange 87 is formed in the bottom 75a of the recess 75. Since it is slidably fitted in the hole 96, it moves downward while maintaining a stable state.

After the resin in the product cavity 43 is cooled and solidified, the fixed mold 41 and the movable mold 42 are opened to take out the resin in the product cavity 43, that is, the molded product. After releasing the molded product from the product cavity 43 in this manner, as shown in FIG.
When air is supplied to the inflow port 105 of the cylinder body 70 from the passage 109 formed in the above, the air flows into the cylinder bodies 70 and 71 from the inflow port 105 and the branch passage 106. As a result, the pistons 82 and 83 move upward in the figure. That is,
The exterior body 66 and the valve pin 67, which form the valve body 56, move upward in the figure almost integrally and, as shown in FIG.
The valve pin 67 is removed from the outer casing 66, and the outer casing 66 moves to the upper portion of the opening 58c of the material passage 58, and the opening 58c is opened.
As a result, when the gate 50 is closed, a wide space is formed in the portion where the exterior body 66 was present.
Then, the mold is closed again and the above molding cycle is repeated, but throughout the entire molding cycle, the resin in the material passage 48 is always kept in a molten state by the heating of the heater 60 like the resin in the runner 48 of the manifold 47. Be drunk

According to the construction of the valve device 51 of the above-mentioned embodiment, the valve body 56 is constituted by the exterior body 66 and the valve pin 67 slidably supported in the exterior body 66. And the valve pin 67 are independently driven by the respective pistons 82 and 83, and when the gate 50 is closed,
Since the valve body 67 is controlled to operate by delaying the valve pin 67 after closing the gate 50 by advancing only the thin valve pin 67 in a state where the exterior body 66 provided on the outer periphery of the valve pin 67 is stopped, Although the resin filled in the valve support hole 57 communicating with the gate 50 is pushed toward the gate 50, the amount of resin pushed by the valve pin 67 can be significantly reduced by lowering only the thin valve pin 67. it can. Thus, after closing the gate 50 with the valve pin 67, the exterior body 66 having a large cross-sectional area is lowered, but since the gate 50 is blocked by the valve pin 67, the resin filled in the valve support hole 57 is exteriorized. Even if the resin is pushed by the body 66, the resin does not flow from the gate 50 into the product cavity 43 and escapes into the gap 65a between the outer surface of the valve body 52 and the inner surface of the hole 49, so that the product is molded. There is no risk of causing defects. At the same time, after closing the gate 50 with the valve pin 67 and lowering the exterior body 66, the exterior body 66 allows the opening 58 of the material passage 58 to be opened.
Since c is closed and the resin is not supplied to the valve support hole 57, the resin pressure is not applied to the valve pin 67 that closes the gate 50. Therefore, even if the thin valve pin 67 is used, the valve pin 67 is not deformed by the pressure of the resin. Furthermore, when the outer casing 66 and the valve pin 67 are moved upward after the molding resin is released from the product cavity 43,
When the gate 50 is closed, a wide space is formed in the portion where the exterior body 66 was present. That is, the amount of resin remaining in the gap 65a between the outer surface of the valve body 52 and the inner surface of the hole 49 is very small. Therefore, for example, when the color of the product is changed, the resin before remaining in the gap 65a can be promptly and reliably discharged without remaining with a small number of shots. Therefore, the waste of the molding material can be reduced and the productivity is improved. Further, the material passage 58 is eccentric with respect to the central axis of the valve support hole 57, and the bent portion 58a formed in the lower portion of the material passage 58 is opened to the lower peripheral surface of the valve support hole 57 communicating with the gate 50. Thus, the resin as the molding material flows into the valve support hole 57 from the bent portion 58a of the material passage 58, and further flows into the gate 50 from the valve support hole 57. At this time, the outer cylinder 66 and the valve pin 67
Is located above the valve support hole 57 communicating with the gate 50 in the figure, and the outer cylinder body 66 and the valve pin 67 do not block the resin flow path. This allows the material passage 58 to pass through the valve support hole.
It is possible to smoothly flow into the product cavity 43 via the gate 57 and the gate 50 to enhance the fluidity of the resin. Also,
The pistons 82 and 83 that drive the exterior body 66 and the valve pin 67 are
A through hole 97 and a bottom wall portion 80, which form guide cylinder portions 88 and 89 and shaft portions 92 and 93, which project vertically in the center portion, in the pressing plate 81.
Through hole 95 formed in the bottom 75a of the recess 75
Each cylinder chamber 77a, 78a while being slidably supported by
It is slidably fitted on the inner peripheral surface of the. Further, the guide cylinder portion 88 of the piston 82 and the shaft portion 93 of the piston 83 are provided in the through hole 95 formed in the bottom wall portion 80 interposed between the cylinder chambers 77a and 78a.
And are fitted coaxially with each other, and a slide guide portion 100 that slidably supports the guide cylinder portion 88 is formed to project from the peripheral edge of the through hole 95, so that the exterior body 66 and the valve pin 67 are driven. At this time, the pistons 82 and 83 can be stably slid along the inner peripheral surfaces of the cylinder chambers 77a and 78a. That is, in this embodiment, the exterior body 66 and the valve pin 67 are independently controlled by the pistons 82 and 83, respectively.
When closing the valve pin 67, the valve pin 67 is operated in advance, but the piston 83 that drives the valve pin 67 has the shaft portion 92 protruding upward from the central portion slidably in the through hole 97 formed in the pressing plate 81. The shaft portion 93 that is guided and projects downward from the central portion of the piston 83 is slidably supported by the guide cylinder portion 88 of the piston 82 that is provided coaxially with the slide guide portion 100 formed on the bottom wall portion 80. To be done. On the other hand, the piston 82 that drives the exterior body 66
The guide cylinder portion 88 protruding upward from the central portion of the upper flange portion 86 is formed by the slide guide portion 100 and the shaft portion 9 of the piston 83.
On the lower side of the piston 82, a guide tube portion 89 projecting from the central portion of the lower flange portion 87 is slidably supported by the through hole 96 on the bottom portion 75a of the concave portion 75. It In this way, when the pistons 82, 83 are moved up and down, the guide cylinder portion 88 and the shaft portion 93 formed on the pistons 82, 83 are supported slidably with each other, and further, the guide cylinder portion 88.
From the peripheral edge of the through hole 95 of the bottom wall portion 80 that fits with the sliding guide portion 100.
By integrally forming the, the contact area between the sliding guide portion 100 and the guide cylinder portion 88 also becomes large. Therefore, the pistons 82 and 83 can be supported in a more stable state, the operations of the pistons 82 and 83 are stabilized, and the exterior body 66 and the valve pin 67 can be reliably driven.

The present invention is not limited to the above embodiment, and various modifications can be made. For example,
In the above embodiments, the case where the cylinder device is an air cylinder device has been described, but the present invention can be applied to other fluid pressure cylinder devices such as a hydraulic cylinder device. Further, although the valve pin is eccentric with respect to the central axis of the material passage in the above embodiment, the valve pin may be positioned coaxially with the main portion of the material passage.

[0032]

According to the valve gate type mold apparatus of the first aspect of the present invention, the exterior body and the valve pin are driven independently of each other, and when the gate is closed, only the thin valve pin is advanced to move the gate. After the valve pin is closed, the valve pin is controlled to operate with a delay, so that the amount of resin pushed by the valve pin can be significantly reduced. Further, by closing the gate with the valve pin and then lowering the exterior body, the resin pushed by the exterior body does not flow into the product cavity from the gate, so that there is no risk of defective molding of the product. Furthermore, when the outer casing and the valve pin are moved upward after demolding the molding resin, a wide space is formed in the part where the outer casing existed, and the amount of resin remaining in the gap between the valve body and the mold. Also few. Therefore, for example, when the color of the product is changed, the resin can be promptly and surely discharged without remaining, the waste of the molding material can be reduced, and the productivity is improved.

According to the valve gate mold apparatus of the second aspect of the invention, in addition to the effect of the first aspect of the invention, the molding material flows smoothly toward the gate without being restricted by the valve body. , The fluidity of the molding material is increased.

According to the valve gate mold apparatus of the third aspect of the invention, in addition to the effect of the second aspect of the invention, after the gate is closed by the valve pin, the resin flowing through the material passage is shut off by the exterior body, Excessive resin pressure is not applied to the valve pin that closes the gate. Accordingly, when a thin valve pin is used, it is possible to prevent the valve pin from being deformed.

According to the valve gate mold apparatus of the fourth aspect of the present invention, in addition to the effect of the first aspect of the invention, when the outer casing and the valve pin are driven, each piston is placed on the inner peripheral surface of each cylinder chamber. It is possible to slide along the surface stably. As a result, the operation of the piston is stable, and the exterior body and the valve pin can be reliably driven.

According to the valve gate mold apparatus of the fifth aspect of the invention, in addition to the effect of the fourth aspect of the invention, the contact area between the partition wall portion and the guide cylinder portion also becomes large, so that the operation of each piston is performed. More stable.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a valve gate type mold device of the present invention.

2 is a sectional view showing a gate portion of the same as above, FIG.
2A shows a state in which the gate is closed, and FIG.
The state where the exterior body is lowered is shown.

FIG. 3 is a cross-sectional view of a thin lider portion that drives the valve body of the same as above, showing a state in which a gate is opened.

FIG. 4 is a cross-sectional view of a thin lider portion that drives the valve body, showing a state in which the gate is closed by a valve pin.

FIG. 5 is a cross-sectional view of the thin lider portion that drives the valve body, showing a state in which the gate is closed by the valve pin and the exterior body.

FIG. 6 is a sectional view showing an example of a conventional valve gate mold apparatus.

[Explanation of symbols]

41 Fixed type 42 Movable type 43 Product Cavity 48 runners (material passage) 50 gates 51 valve device 53 Valve casing 56 valve body 57 Valve support hole 58 Material passage 58a Bending part 60 heater (heating means) 66 Exterior 67 Valve pin 70,71 cylinder device (drive means) 77a, 78a Cylinder chamber 82, 83 pistons 80 Bottom wall (partition wall) 95 through holes 88, 89 Guide tube 92, 93 shaft 100 sliding guide

Claims (5)

[Claims] 1. A plurality of molds which are opened and closed to form product cavities between them when the molds are closed, and a valve device which opens and closes a gate for communicating a material passage provided in the molds with the product cavities. The valve device includes a valve casing having a material passage formed therein and heating means for heating the material passage, a valve body for opening and closing the gate, and a drive means for driving the valve body. In the gate type mold device, the valve body is composed of a sleeve-shaped exterior body and a valve pin that slides along the inner peripheral surface of the exterior body to open and close the gate, and the driving means includes the exterior body. The body and the valve pin are independently controllable, and after the gate is closed by the valve pin, the outer body is delayed and actuated. Valve gate type mold device. 2. A valve body support hole is formed in the valve casing so as to concentrically penetrate through the valve casing, the valve body support hole slidably supporting the valve body support hole and the valve body support hole. The center axis of the hole and the center axis of the material passage are eccentric, and the lower portion of the material passage is bent to communicate with the valve body support hole.
Valve gate type mold device described. 3. The material passage is configured to be opened and communicated with a lower peripheral surface of the valve body supporting hole located at the end portion on the gate side, and the opening portion is opened and closed by the exterior body. The valve gate mold apparatus according to claim 2, which is characterized in that. 4. The drive means is composed of a cylinder body coaxially provided and a piston slidably provided in the cylinder chamber of each cylinder chamber, and the valve pin is fixed to one of the pistons. At the same time, the outer casing is fixed to the other piston, a partition wall portion having a through hole is interposed between the pistons, and a guide cylinder portion that slides along the through hole is formed in the one piston. At the same time, the other piston is provided with a shaft portion that slides along the inner peripheral surface of the guide cylinder portion. 5. A sliding guide portion is formed by extending substantially cylindrically from a peripheral portion of a through hole formed in the partition wall portion, and the guide cylindrical portion is slidably supported by the sliding guide portion. The valve gate mold apparatus according to claim 4, which is characterized in that.