JP2002355857A - Valve gate-type mold assembly - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the cooling performance, at a gate spot, of a finished product cavity. SOLUTION: A gap 54 making up a heat insulating layer is formed between the tip side of a valve casing 26 and the inner face 23A, on the gate 20 side, of a built-ion hole 23. In addition, a sealing ring 57 as an annular sealing member for sealing the gap 54 is provided on the inner peripheral face of a material passage 28, at the tip part 33 of the valve casting 26. Further, liquid channels 81 and 81 for cooling are formed near the gate 20. It is possible to quench a resin at the gate 20 spot of a product cavity 3 by the combination of a heating insulating air layer formed by the gap 54 and liquid channels 81 and 81 for cooling near the gate 20.

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, and is used for injection molding of a thermoplastic resin such as PET (polyethylene terephthalate).

[0002]

A hot runner mold apparatus used for injection molding of a thermoplastic resin heats a resin in a material passage to a gate to a product cavity and constantly melts the resin in order to increase molding efficiency. It is something that keeps the state.
On the other hand, since the resin in the product cavity to be a product must be cooled and solidified, the hot runner mold device needs to open and close the gate by some means. As a gate opening / closing method, there is a valve gate method in which a gate is mechanically opened / closed by a valve pin.

In a valve gate type mold apparatus, as described in, for example, Japanese Patent Application Laid-Open No. Hei 5-177664, a valve pin is built in a valve casing having an internal material passage and a heater provided on the outer peripheral side. I have. As described above, the resin in the material passage is always kept in a molten state by the heating of the heater, but the resin filled in the product cavity must be cooled in order to solidify. Moreover, in order to increase the molding efficiency, it is desirable to cool quickly. Therefore, thermal insulation between the valve casing and the fixed main body in which the valve casing is incorporated is important. For this heat insulation, a gap that forms a heat insulating layer is formed between the outer surface of the heater cover that covers the valve casing and the heater and the inner surface of the mounting hole of the fixed main body that incorporates the valve casing and the heater. And the inner surface of the mounting hole is in contact with only a small area. Since the gap communicates with the gate,
The resin as the molding material enters. In the gap, the resin penetrates from the gate side to the first contact portion between the valve casing and the inner surface of the mounting hole. Therefore, up to this point, the heat insulating layer is made of a resin, and the side opposite to the gate from the first contact portion becomes the air heat insulating layer. Since the air heat insulating layer has a higher heat insulating effect than the resin heat insulating layer, in the mold apparatus described in the above publication, a metal is provided between the outer surface of the valve casing and the inner surface of the mounting hole at a position relatively close to the gate. An O-ring is interposed to increase the number of air insulation layers as much as possible. However, since the resin also infiltrates up to the metal O-ring, the heat insulating effect is lower than that of the air heat insulating layer.

By the way, a molded product or preform of PET is molded by the valve gate type mold apparatus as described above, and the molded product or container made of PET has characteristics excellent in transparency and gas barrier properties. ing.

[0005] The melting temperature of PET is higher than other thermoplastic resins, and a relatively large capacity heater is required to keep the resin in the valve casing at a high temperature.
Further, if the PET is not cooled immediately after the injection, it is crystallized by heat and turbidity occurs, and there is a problem that turbidity tends to occur particularly at the gate portion of the product cavity.

SUMMARY OF THE INVENTION The present invention is intended to solve such a problem, and it is possible to improve the heat insulation between the valve casing side and the gate portion and to improve the cooling performance of the gate portion of the product cavity. It is an object of the present invention to provide a mold apparatus.

[0007]

According to a first aspect of the present invention, there is provided a valve gate type mold apparatus, wherein a plurality of molds are opened and closed with each other to form a product cavity therebetween when the mold is closed. A valve device provided in a mold having an opening gate, the valve device being incorporated in an assembling hole formed in the mold and having a material passage formed therein; and a valve casing. And a valve pin provided inside the valve casing to open and close the gate, and heat insulation is provided between the outer surface on the tip side of the valve casing and the inner surface on the gate side of the mounting hole of the mold. An annular sealing member for sealing the gap is provided on the inner peripheral surface of the material passage at the tip end of the valve casing; In the vicinity of the bets it is provided with a cooling liquid passage.

In molding, after closing a plurality of molds, a valve pin is moved to open a gate. In this state, the molding material is injected from the molding machine. The molding material is filled from the gate into the product cavity through the material passage in the valve casing and through the annular sealing member. Thereafter, the valve pin moves and engages the gate, and the gate is closed. Further, after the molding material in the product cavity, that is, the product is solidified, the mold is opened to take out the molded product. During that time, the molding material in the material passage of the valve casing is always kept in a molten state by the heating of the heater.

The gap between the outer surface of the valve casing and the inner surface of the gate side of the mounting hole of the mold at the tip of the valve casing is sealed by a sealing member, so that the molding material is filled in the gap. A heat-insulating air layer is formed between the valve casing to be heated and the product cavity to be cooled without gaps, thereby ensuring heat insulation between the valve casing side and the gate portion of the product cavity. it can.

In addition, the gate portion can be effectively cooled by the cooling liquid passage provided in the vicinity of the gate, and the resin at the gate portion can be effectively cooled by the combination of the cooling liquid passage and the adiabatic air layer. Cooling.

According to a second aspect of the present invention, in the valve gate type mold apparatus according to the first aspect of the present invention, the cooling liquid passage is provided on a side of the gap.

The cooling performance of the resin at the gate can be further improved by the air heat insulating layer and the cooling liquid passage provided on the side of the gap to be the air heat insulating layer.

According to a third aspect of the present invention, in the valve gate type mold apparatus according to the first aspect of the present invention, the gap increases from the gate side to the heater side.

Since the distance between the outer surface of the valve casing and the inner surface of the mounting hole in the gap is larger as it is closer to the heater, an effective heat insulating structure for preventing the transfer of heat from the heater side to the gate side can be obtained.

According to a fourth aspect of the present invention, in the valve gate type mold apparatus according to the third aspect of the present invention, in the valve gap,
The distal end outer surface of the valve casing and the gate-side inner surface of the mounting hole are enlarged from the gate side toward the base end side of the valve casing, and the gate-side inner surface of the mounting hole is larger than the distal end outer surface of the valve casing. It is something to expand.

Accordingly, the gap is set so as to be larger on the heater side.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a valve gate type mold apparatus according to the present invention will be described below with reference to the drawings. First, an embodiment will be described with reference to FIGS.
First, the configuration of the injection molding die apparatus will be described. 1 is the first
The fixed mold 2 and the movable mold 2 are movable molds as the second mold body. The fixed mold 1 and the movable mold 2 move in the vertical direction (mold opening and closing direction) in the figure to open and close with each other. A product cavity 3 having a product shape is formed therebetween.

The fixed mold 1 is fixed to first and second fixed mold plates 5 and 6 forming the product cavity 3 and a back side (opposite to the movable mold 2) of the fixed mold plate 6. A fixed-side receiving plate 7 and a fixed-side mounting plate 9 fixed to the back side of the fixed-side receiving plate 7 via a spacer block 8 are provided. Incidentally, the second fixed side mold plate 6 has a concave portion 4 forming the product cavity 3. The fixed side mounting plate 9 is mounted on a fixed side platen (not shown) of the injection molding machine. A fixed ring 9 and a sprue bush 13 to which a nozzle 12 of a heating cylinder device which is a molding material supply device of an injection molding machine is connected are fixed to the fixed mounting plate 9. The inside of the sprue bush 13 is a sprue 14 which is a material passage. Further, the sprue bush 13 is provided with a heater 15 as heating means for heating the sprue 14 and keeping the thermoplastic resin as a molding material in the sprue 14 in a molten state at all times. In addition, a manifold 16 is provided between the fixed-side receiving plate 7 and the fixed-side mounting plate 8. Inside the manifold 16, a runner 17 is formed as a material passage for branching the sprue 14 into each product cavity 3. In addition, a runner
A heater 18 is provided as heating means for heating 17 to keep the thermoplastic resin therein constantly in a molten state.

The fixed type 1 has a direct gate 20.
A valve device 21 as a gate opening / closing means for opening / closing the valve is incorporated. Next, the configuration of the valve device 21 will be described. The fixed side receiving plate 7 constituting the main body of the fixed mold 1 is formed with a built-in hole 22 penetrating in the mold opening / closing direction. Further, inside the fixed side mold plate 6 serving as the main body, An assembling hole 23 is formed to communicate with the assembling hole 22. At the tip of the assembling hole 23, the gate 20 is provided so as to communicate with the product cavity 3. A substantially cylindrical valve casing 26 is installed in the installation holes 22 and 23. One end of the valve casing 26 forms a flange 27 and is fixed to the manifold 16 and the fixed-side receiving plate 7.

The inside of the valve casing 26 is a material passage 28 for communicating the runner 17 in the manifold 16 with the gate 20. The material passage 28 has a substantially cylindrical straight portion 28A whose axial direction is the mold opening and closing direction, and an inlet portion 28B obliquely provided from an end of the straight portion 28A opposite to the gate 20. The entrance 28B communicates with the runner 17.

A material passage of the valve casing 26 is provided.
On the inner peripheral surface of the tip portion 33 on the gate 20 side in 28, the gate 20
And three support blades 29 as valve pin support portions extending in the mold opening and closing direction at an interval.
These support blades 29 are located at 120 ° with respect to the central axis of the material passage 28.
° radially apart from each other. The support blade 29
On the inner edge of the material passage 28, a portion opposite to the gate 14 (upper portion in FIG. 1) is a concave arc-shaped curved portion 30, but the other portion is orthogonal to the mold opening / closing direction and is inside the material passage 28. The lower edge 30A reaches the peripheral surface. The curved portion 30 of the support blade 29 is for reducing the resistance to the flow of the resin as the molding material. The groove-shaped portion between the support blades 29 is a divided material passage portion 31. Since these divided material passages 31 have three support blades 29, they form three divided passages. The support blade 29 is relatively thin, and the width of the divided material passage portion 31 is much larger than the width of the support blade 29. The support blade 29 is formed near the tip of the valve casing 26, and the inner peripheral surface of the valve casing 26 is a cylindrical portion 32, and from the cylindrical portion 32 toward the center of the valve casing 26, The support blade 29 is formed integrally. The valve casing 26 integrally including the support blade 29 can be manufactured by, for example, electric discharge machining.

The valve casing 26 incorporates a valve pin 36 as a valve body that opens and closes the gate 20 by moving in the mold opening and closing direction by driving a driving device such as a hydraulic cylinder provided on the fixed-side mounting plate 9. Have been. The valve pin 36 closes the gate 20 by a gate closing portion 37 formed at the tip end on the gate 20 side being removably fitted to the gate 20. Also, valve pin 36
The axial direction is the mold opening / closing direction, and the outer peripheral surface is always slidably in contact with the inner edge of the support blade 29 of the valve casing 26. This allows the gate of the valve pin 36
The tip on the 20 side is supported. In addition, valve pin 36
Is supported at the end on the manifold 16 side of the valve casing 26 by a guide bush 38 as a valve pin support fixed inside the valve casing 26. That is, the inside of the guide bush 38 is
Are slidably penetrated. The proximal end of the valve pin 36 is connected to a vertically moving piston 40 of a hydraulic cylinder device 39.
It is connected to. A band heater 41 for heating the material passage 28 and a substantially cylindrical heater cover 42 for covering the heater 41 from outside are fitted on the outer peripheral surface of the valve casing 26. A band heater 43 for heating the material passage 28 and a substantially cylindrical heater cover 44 for covering the heater 43 from outside are fitted on the outer peripheral surface of the flange portion 27.

An installation hole fitting portion 51 is provided on the distal end side of the valve casing 26, and the outer peripheral surface of the installation hole fitting portion 51 has a cylindrical fitting surface of the same diameter formed in the installation hole 23. 52 is fitted to the base end side fitting position 52A. As a result, the valve casing 26 is supported by the fixed mold plate 6. A flat portion 53 is provided at a front end of the fitting portion 51, and a front end portion 33 of the valve casing 26 is provided from a center of the flat portion 53.
Is protruding. In addition, for heat insulation, 2
2, 23 inner surface, valve casing 26 and heater cover 4
The gaps 54 and 55 are formed between the outer surface of the second and the outer surface of the second. Further, the gap 54 on the distal end portion 33 and the gap 55 on the heater 41 side are shut off by fitting the fitting hole fitting portion 51 and the fitting surface 52. A cylindrical component as a sealing member for closing the distal end of the gap 54 is provided at the distal end 33 of the valve casing 26.
A sealing ring 57 composed of 56 is provided. The outer surface 58 of the sealing ring 57 is generally
A cylindrical chamfered portion 59 is formed on the outer periphery of the tip end on the gate 20 side. The cylindrical portion of the valve casing 26
As shown in FIGS. 4 and 5, the height H of the sealing ring 57 incorporated in the valve 32 is smaller than the distance S from the lower edge 30A of the supporting blade 29 integrally formed in the valve casing 26 to the gate 20. Is set to short. Thus, the sealing ring 57 is slidably assembled in the mold opening / closing direction along the cylindrical portion 32 of the valve casing 26 between the support blade 29 and the gate 20. Further, a through hole 60 for the valve pin 36 is formed in the sealing ring 57. This through hole 60
A tapered surface 61 that opens toward the material passage 28 and narrows toward the gate 20 is formed at the end of the tapered surface 61.
The tip opening 61 of the sealing ring 57 is formed to have the same diameter as the gate 20. In addition, the sealing ring 57 is formed of a metal or a metal having excellent heat resistance and abrasion resistance that is not melted by heat of a molding material such as a resin molded by the present mold apparatus. The molding material injected from the material passage 28 side during molding is a sealing ring 57.
When passing through the through-hole 60 of the 57, the pressure moves to the injection direction of the molding material, that is, toward the gate 20, and the tip end surface of the sealing ring 57 contacts the peripheral edge of the gate 20.

The movable mold 2 is provided with the first fixed mold plate 5.
The movable mold plate 72 is fixed to a core 73 that forms an inner surface of the product cavity 3. A movable receiving plate (not shown) is fixed to a surface of the movable die plate 72 opposite to the fixed die 1. An injection molding machine is provided on a surface of the movable receiving plate opposite to the fixed die 1. The movable-side mounting plate attached to the movable-side platen is fixed via a spacer block. The protruding plate 71 is drivable in a direction away from the movable mold plate 72, and protrudes the molded product from the core 73. In addition, the core
A cooling liquid passage 74 is provided in 73, and the cooling liquid passage 74 has a hole 75 formed in the core 73, and a pipe member 76 is formed in the hole 75.
In FIG. 2, the cooling water pumped into the pipe member 76 from below flows downward from the distal end of the pipe member 76 through the space between the outer periphery of the pipe member 76 and the hole 75 in FIG.

The stationary mold plate 6 is provided with cooling liquid passages 81 near the gate 20. The cooling liquid passages 81 are provided with the gap 54 interposed therebetween, and the mold opening / closing direction is provided. As shown in FIG. 6,
The cooling liquid passages 81, 81 are formed in substantially parallel straight lines on both sides of the gate 20, and the cooling fluid flows in opposite directions through the cooling liquid passages 81, 81 on both sides as shown by arrows. Further, in the mold opening / closing direction, the cooling liquid passage 81 is provided at a position corresponding to the gap 54 on the gate 20 side from the fitting position 52A. Further, the fixed-side mold plate 6 and the fixed-side receiving surface 7
The fixed side mold plate 6 is provided with a cooling liquid passage 82 substantially surrounding the mounting hole 22, and the cooling liquid passage 82 includes an inflow port 83 and a discharge port 83 (not shown). Is connected, the cooling liquid sent from the inflow port 83 passes through the cooling liquid passage 82, and after substantially making a round around the built-in hole 22,
The liquid is discharged from the discharge port.

The first fixed side mold plate 5 has a female mold 91 forming the product cavity 3, and the female mold 91 is a nest having a cylindrical shape, and the female mold 91 is mounted. A mounting hole 92 is formed in the stationary template 5. The female body 91 has a flange portion 93, and a step 94 to which the flange portion 93 is mounted is formed in the mounting hole 92.

In the mating surface of the flange 93 of the female body 91 and the fixed-side receiving surface 6, the flange 93 has a recess 4
Is provided with a cooling liquid passage 101. Also,
A plurality of cooling liquid passages 102, 102 are provided on the outer peripheral surface of the female mold 91.
A, 102B, 102C, 102D, and 102E are formed.

Next, the operation of the above configuration will be described. In molding, first, the mold clamping device of the injection molding machine closes the fixed mold 1 and the movable mold 2 with a fixed mold clamping force.
By closing the mold, the core 73 of the movable mold 2 is inserted into the concave portion 4 of the fixed mold 1 and the male mold body 91, and the product cavity 3 is formed therebetween. As shown in FIG. 4, the valve 20 is moved away from the movable mold 2 to open the gate 20. In addition,
Even when the gate 20 is open, the valve pin 36 remains fitted to the support blade 29 of the valve casing 26. Then, a molten thermoplastic resin, for example, PET, which is a thermoplastic molding material, is injected into the fixed mold 1 from the injection molding machine. This resin (not shown) passes through the runner 17 of the manifold 16 and the like, and further passes through a material passage 28 in the valve casing 26, a divided material passage portion 31 between the supporting blades 29 in which the valve pins 36 are fitted, and a cylindrical portion. Seal ring 57 fitted to 32
Flows from the gate 20 into the product cavity 3 through the through hole 60 in the inside. At this time, the cylindrical portion of the valve casing 26
The sealing ring 57 slidably fitted to the 32 is pushed out toward the gate 20 by the pressure of the molten thermoplastic resin as a molding material, and the tip of the sealing ring 57 contacts the peripheral edge of the gate 20. Thereby, the gap 54 between the distal end portion 33 of the valve casing 26 and the inner surface of the mounting hole 23 of the fixed mold plate 6 is sealed by the sealing ring 57. After the resin is filled into the product cavity 3 in this manner, the valve pin 36 moves toward the movable mold 2 as shown in FIG.

At the time of such molding, the gap 54 between the valve casing 26 and the fixed mold plate 6 provided with the gate 20 is sealed by the sealing ring 57, so that the gap 54 is formed.
The resin of the molding material does not penetrate into the mold. At the same time, an air heat insulating layer is formed by the gap 54 between the valve casing 26 to be heated by the sealing ring 57 and the gate 20 to be cooled, so that excellent heat insulating properties can be secured.

The resin filled in the product cavity 3 is supplied to the cooling liquid passages 74, 81, 82, 101, 102, 102A and 102.
The cooling liquid flowing through B, 102C, 102D, and 102E is cooled. At this time, the cooling liquid passage 8 is located near the gate 20.
1 and 81, these cooling liquid passages 8
The resin in the product cavity 3 at the 20 gates can be rapidly cooled by the cooling liquid flowing through 1,81. In particular, P
When a resin such as ET is used, the high-temperature resin filled in the product cavity 3 is rapidly cooled to prevent generation of a cloudy portion due to heat. And, the valve casing 26 is provided with a material passage.
In order to keep the resin in the molten state in the molten state, the heater 41 keeps the resin in a high temperature state, whereas a gap 54 that serves as an air insulating layer is provided between the gate 20 and the tip 33 of the valve casing 26. By providing the cooling liquid passages 81 and 81 in the vicinity of the gate 20, cooling can be performed while ensuring heat insulation, and rapid cooling of the resin at the gate 20 in the cavity 3 becomes possible. Further, since the distance between the outer surface 33A of the distal end portion 33 of the valve casing 26 and the inner surface 23A of the mounting hole 23 in the gap 54 is set to be larger as the distance from the heater 41 increases, the distance from the valve casing 26 side to the gate 20 side increases. An effective heat insulating structure for preventing the transfer of heat is obtained.

After the resin in the product cavity 3, ie, the product, is cooled and solidified, the fixed mold 1 and the movable mold 2 are opened, and the molded product is taken out. Thereafter, the mold is closed again, the above steps are repeated, and the molding is repeated. During that time, the resin in the material passage 28 of the valve casing 26 is always kept in a molten state by the heating of the heaters 41 and 43.

The valve casing 26 includes a heater 4
The sealing ring 57 is slidably provided between the lower end edge 30A of the supporting blade 29 formed integrally with the inner peripheral surface of the valve casing 26 and the gate 20 by the thermal expansion caused by the heating of 1, 43. Since it is assembled, it does not receive a strong pressure from the valve casing 26 due to the thermal expansion of the valve casing 26. That is, the height H of the sealing ring 57 is set slightly shorter than the distance S from the lower edge 30A of the support blade 29 formed integrally with the inner peripheral surface of the valve casing 26 to the gate 20, so that the support blade It is freely movable between 29 and gate 20. For this reason, the valve casing
Even if the thermal expansion occurs in 26 and the sealing ring 57 expands,
There is no danger that the sealing ring 57 slides along the columnar portion 32 formed at the tip of the valve casing 26 and is strongly pressed against the gate 20 following the thermal expansion of the valve casing 26 to be deformed. Thus, the gap 54 between the distal end portion 33 of the valve casing 26 and the mounting hole 23 can be reliably sealed by the sealing ring 57, and the heat insulating effect of the gap 54 is not impaired. At the same time, the sealing ring 57
Is manufactured separately from the valve casing 26 and is slidably incorporated into the cylindrical portion 32 of the valve casing 26. Therefore, even if a slight dimensional error or an assembly error occurs in the sealing ring 57, the sealing is performed. By sliding the stop ring 57, the sealing ring
Since the dimensional error and the assembly error of the sealing ring 57 can be absorbed, and strict dimensional control is not required for manufacturing the sealing ring 57, the manufacturing process of the sealing ring 57 is easy. As described above, the sealing ring 57 is slidably incorporated in the valve casing 26 so that the sealing ring 57 does not receive a strong pressure from the valve casing 26 due to the thermal expansion of the valve casing 26. Even if an error occurs, the error can be absorbed. Further, the through hole 60 of the sealing ring 57 slidably incorporated in the valve casing 26 is formed with a tapered surface 61 that increases resistance to the flow of the molten thermoplastic resin, so that the molten thermoplastic resin When the resin passes through the through-hole 60, the sealing ring 57 can reliably contact the peripheral edge of the gate 20 by the pressure of the thermoplastic resin to seal the gap 54 between the valve casing 26 and the mounting hole 23. . Therefore, when injecting resin, the gate
The sealing effect of the sealing ring 57 can be maintained without the thermoplastic resin leaking into the gap 54 by separating the sealing ring 57 from 20.

As described above, according to the first embodiment, the fixed mold 1 and the movable mold 2 which are a plurality of molds that open and close to each other and form a product cavity therebetween when the mold is closed, and these molds And a valve device 21 provided on the fixed mold 1 which is a mold having a gate 20 opening to the product cavity 3. The valve device 21 is incorporated into an installation hole 23 formed in the fixed mold 1. A valve casing 26 having a material passage 28 formed therein, a heater 41 provided in the valve casing 26, and a valve pin 36 provided in the valve casing 26 for opening and closing the gate 20. A gap 54 forming a heat insulating layer is formed between the outer side surface 33A and the inner surface 23A on the gate 20 side of the mounting hole 23 of the fixed mold 1, and a front end portion 33 of the valve casing 26 is formed.
A sealing ring 57, which is an annular sealing member for sealing the gap 54, is provided on the inner peripheral surface of the material passage 28, and cooling liquid passages 81, 81 are provided near the gate 20. The outer surface 33A of the valve casing 26 and the fixed mold 1
A gap 54 between the mounting hole 23 and the inner surface 23A on the gate 20 side is sealed by a sealing ring 57, so that a gap is provided between the valve casing 26 to be heated and the product cavity 3 to be cooled. A heat insulating air layer is formed by 54, whereby heat insulation between the valve casing 26 side and the gate 20 of the product cavity 3 can be ensured. In addition, the cooling liquid passages 81 provided near the gate 20 can effectively cool the gate 20. Therefore, the combination of the insulating air layer formed by the gap 54 and the cooling liquid passages 81 and 81 near the gate 20 enables rapid cooling of the resin at the gate 20, and the molding of the product cavity 3 in the molding using PET as the resin material. Opacity of the resin at the 20 gates can be prevented.

Further, in this embodiment, since the cooling liquid passages 81 and 81 are provided on the sides of the gap 54 according to the second aspect, the air insulation layer and the gap 54 serving as the air insulation layer are provided.
The cooling liquid passages 81, 81 provided on the sides of
The cooling performance of the resin in the product cavity 3 at the gate 20 can be improved.

Further, in this embodiment, the gap 54 increases from the gate side to the heater 41 side, so that the heat transfer from the heater 41 side to the gate 20 side corresponds to the third aspect. An effective heat insulating structure can be obtained in order to prevent the above.

Further, in the present embodiment, as described above, in the gap 54, the valve casing 26
The outer surface 33A of the distal end portion 33 and the inner surface 23A of the mounting hole 23 on the gate 20 side expand from the gate 20 side toward the base end side of the valve casing 26, and the inner surface 23A of the mounting hole 23 on the gate 20 side is a valve. Outer surface 33A of tip 33 of casing 26
Since the gap 54 is larger, the gap 54 can be set to be larger toward the heater 41.

The fitting position 52A of the valve casing 26
A gap 54 is provided on the gate 20 side, and the fitting position 52A and the gate
Cooling liquid passages 81 are provided between the valve casing 26 and the product cavity 3 at a position closer to the gate 20 than the fitting position 52A. 52A valve casing 26 and mounting hole 23
Are in contact with each other, the cooling liquid passages 81, 81 provided between the fitting position 52A and the position near the gate 20 allow the heater 41
The transfer of heat transmitted from the gate through the fitting position 52A to the product cavity 3 at the gate 20 can be suppressed.

It should be noted that the present invention is not limited to the above embodiment, and various modifications can be made.

[0039]

According to the valve gate type mold apparatus of the first aspect of the present invention, a gap forming a heat insulating layer is formed between the outer surface on the tip side of the valve casing and the inner surface on the gate side of the mounting hole of the mold. In addition, an annular sealing member for sealing the gap is provided on the inner peripheral surface of the material passage at the distal end of the valve casing, and a cooling liquid passage is provided near the gate. The combination of the air layer and the cooling liquid passage near the gate enables rapid cooling of the product cavity at the gate.

According to the valve gate type mold apparatus of the second aspect of the present invention, in addition to the effect of the first aspect of the present invention, the cooling liquid passage is provided on the side of the gap, so that the gate location can be further increased. Cooling performance can be improved.

According to the valve gate type mold apparatus of the third aspect of the invention, in addition to the effect of the first aspect of the invention, the gap increases from the gate side to the heater side. An effective heat insulating structure for preventing heat transfer to the gate side can be obtained.

According to the valve gate type mold device of the fourth aspect of the invention, in addition to the effect of the third aspect of the invention, the gap can be set to be larger on the heater side.

[Brief description of the drawings]

FIG. 1 is a sectional view of a stationary mold side showing one embodiment of a valve gate type mold apparatus of the present invention.

FIG. 2 is a cross-sectional view of the same movable mold side.

FIG. 3 is a sectional view of the valve device.

FIG. 4 is a sectional view of the valve device at the tip end side with the gate opened.

FIG. 5 is a cross-sectional view of the valve device tip side with the gate closed.

FIG. 6 is a cross-sectional view of the cooling fluid passage.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fixed type | mold (mold) 2 Movable type | mold (mold) 3 Product cavity 6 Fixed side template (body part) 7 Fixed side receiving plate (body part) 20 Gate 21 Valve device 22 Mounting hole 23 Mounting hole 23A Inner surface 26 Valve Casing 28 Material passage 28A Straight part 33 Tip 33A Outer surface 36 Valve pin 41 Heater 54 Clearance 57 Sealing ring (sealing member) 81 Cooling liquid passage

Continued on the front page (72) Inventor Hiroshi Ueno 3-1-1 Koganecho, Niigata City, Niigata Prefecture F-term in Mitsubishi Materials Corporation Niigata Works (reference) 4F202 AA24 CA11 CB01 CK07 CN05

Claims (4)

[Claims] A plurality of molds that open and close to each other and form a product cavity therebetween when the mold is closed, and a valve device provided on a mold having a gate that opens to the product cavity among the molds; The valve device includes a valve casing that is incorporated into a mounting hole formed in the mold body and has a material passage formed therein, a heater provided in the valve casing, and a gate provided in the valve casing. A valve pin that opens and closes, and forms a gap that forms a heat insulating layer between the outer surface on the distal end side of the valve casing and the inner surface on the gate side of the mounting hole of the mold body, and a material is formed at the distal end portion of the valve casing. A valve, wherein an annular sealing member for sealing the gap is provided on an inner peripheral surface of the passage, and a cooling liquid passage is provided near the gate. Gate type mold equipment. 2. The valve gate type mold apparatus according to claim 1, wherein the cooling liquid passage is provided on a side of the gap. 3. The valve gate type mold apparatus according to claim 1, wherein the gap increases from the gate side to the heater side. 4. In the gap, the outer surface of the distal end portion of the valve casing and the inner surface of the mounting hole on the gate side are:
4. The valve gate type mold according to claim 3, wherein the inner surface of the mounting hole on the gate side is larger than the outer surface of the distal end portion of the valve casing, while expanding from the gate side toward the base end side of the valve casing. apparatus.