KR20240060030A - Cooling bush for hot runner and hot runner mold with the same - Google Patents

Abstract

A cooling bush for a hot runner and a hot runner mold equipped therewith are disclosed. The disclosed cooling bush for a hot runner includes an outer circumferential flow path forming portion formed on the outer circumferential surface through which a cooling passage for cooling and hardening the molten resin filled in the gate flows through the hot runner portion connected to the gate of the mold core; and a refrigerant inflow passage connected to one side of the cooling passage to allow refrigerant to flow into the cooling passage, and an internal passage forming portion formed therein with a refrigerant outflow passage connected to the other side of the cooling passage to allow refrigerant to flow out of the cooling passage.

Description

Cooling bush for hot runner and hot runner mold equipped with same {COOLING BUSH FOR HOT RUNNER AND HOT RUNNER MOLD WITH THE SAME}

The present invention relates to a hot runner mold having a hot runner therein, and more specifically, to a cooling bush for a hot runner installed at an end of a hot runner, and a hot runner mold having the same.

In order to industrially manufacture plastic products of a specific shape, an injection molding method using an injection mold is applied. Semi-finished products molded and ejected from a traditional injection mold include runner scrap, which causes the problem that raw materials for molding finished plastic products, that is, molten resin, are wasted and the production cost of plastic products increases.

A hot runner mold is known that prevents the generation of runner scrap and suppresses waste of molten resin. The hot runner mold is configured so that the runner that guides the molten resin from the mold to the gate, which is the entrance to the cavity, is heated to a high temperature so that the molten resin injected into the runner does not harden.

In a hot runner mold, if the curing time of the molten resin filled in the gate is delayed compared to the curing time of the molten resin filled in the cavity, the cycle time of injection molding is extended and productivity is reduced. To prevent this problem, a cooling means is provided at the end of the hot runner nozzle. However, the existing cooling means for cooling the end of the hot runner nozzle has a long distance from the gate, so the cooling hardening of the gate is still delayed, and leakage of refrigerant in the refrigerant flow line frequently occurs, resulting in damage to the hot runner mold. , It is difficult to apply when the shape of the plastic product is curved.

The background technology of the present invention is disclosed in Republic of Korea Patent Publication No. 10-1306051 (registered on September 3, 2013, title of invention: Hot runner nozzle for injection molding machine to prevent stringing).

The present invention is intended to solve the above problems, and provides a cooling bush for a hot runner that quickly cools the gate, shortening the cycle time and reducing injection molded product defects, and a hot runner mold equipped with the same.

The present invention includes: an outer circumferential flow path forming portion formed on the outer circumferential surface through which a refrigerant that cools and hardens the molten resin filled in the gate flows through a hot runner portion connected to a gate of a mold core; and a refrigerant inflow passage connected to one side of the cooling passage to allow the refrigerant to flow into the cooling passage, and a refrigerant outflow passage connected to the other side of the cooling passage to allow the refrigerant to flow out of the cooling passage. A cooling bush for a hot runner including a portion is provided.

The cooling flow path includes: a first spiral flow path portion having one end connected to the refrigerant inlet flow path and guiding the refrigerant to flow in a direction away from the internal flow path forming portion along a first spiral trajectory; a second spiral flow path portion whose one end is connected to the refrigerant outlet flow path and which guides the refrigerant to flow in a direction approaching the internal flow path forming portion along a second spiral trajectory that does not intersect the first spiral trajectory; and a connection passage portion connecting the other end of the first spiral passage portion and the other end of the second spiral passage portion to enable refrigerant flow.

The connection passage portion may extend along an arc path centered on an axis extending in the longitudinal direction of the hot runner portion.

The cooling bush for a hot runner of the present invention has a first seal that is in close contact with the internal flow path forming part and the mold core at a position higher than the top of the cooling flow path along the longitudinal direction of the hot runner part to prevent leakage of the refrigerant. wealth; and a second sealing part that is in close contact with the outer circumferential flow path forming part and the mold core at a position lower than the bottom of the cooling flow path along the longitudinal direction of the hot runner part and prevents leakage of the refrigerant.

In addition, the present invention provides a mold having a skin surface defining a cavity, a gate through which molten resin passes when injected into the cavity, and a cooling bush mounting groove. core; A disk that fixedly supports the mold core; A hot runner extends from the inside of the disk and the mold core toward the gate, has a hot runner formed therein, and is connected to the gate so that the molten resin flows from the hot runner to the gate. Runner part; and an outer circumferential flow path forming portion mounted on the cooling bush mounting groove and having a cooling passage formed on the outer peripheral surface through which a refrigerant for cooling and hardening the molten resin filled in the gate through the hot runner portion flows, and the refrigerant flows into the cooling passage. For a hot runner including a refrigerant inflow passage connected to one side of the cooling passage to allow the refrigerant to flow in, and an internal passage forming portion formed therein with a refrigerant outflow passage connected to the other side of the cooling passage to allow the refrigerant to flow out of the cooling passage. A hot runner mold including a cooling bush is provided.

The cooling flow path includes: a first spiral flow path portion having one end connected to the refrigerant inlet flow path and guiding the refrigerant to flow in a direction away from the internal flow path forming portion along a first spiral trajectory; a second spiral flow path portion whose one end is connected to the refrigerant outlet flow path and guides the refrigerant to flow in a direction approaching the internal flow path forming portion along a second spiral trajectory that does not intersect the first spiral trajectory; and a connection passage portion connecting the other end of the first spiral passage portion and the other end of the second spiral passage portion to enable refrigerant flow.

The connection passage portion may extend along an arc path centered on an axis extending in the longitudinal direction of the hot runner portion.

The hot runner mold of the present invention includes a refrigerant supply line connected to the internal flow path forming part so that the refrigerant is supplied to the refrigerant inlet flow path from outside the internal flow path forming part; and a refrigerant discharge line connected to the inner flow path forming portion such that the refrigerant is discharged from the refrigerant outlet flow path to the outside of the inner flow path forming portion, wherein the refrigerant supply line and the refrigerant discharge line are refrigerant lines formed on the disk. It may extend across the disk through a groove and out of the disk.

The cooling bush for the hot runner includes a first sealing part that is in close contact with the inner flow path forming part and the mold core at a higher position than the top of the cooling flow path along the longitudinal direction of the hot runner part to prevent leakage of the refrigerant, And it may further include a second sealing part that is in close contact with the outer circumferential flow path forming part and the mold core at a position lower than the bottom of the cooling flow path along the longitudinal direction of the hot runner part and prevents leakage of the refrigerant.

The inner flow path forming part and the mold core are fastened by a bolt, and as the clamping force of the bolt increases, the first sealing part adheres more strongly to the inner flow path forming part and the mold core, and the second sealing part adheres more tightly to the inner flow path forming part and the mold core. The sealing portion may be in closer contact with the outer circumferential flow path forming portion and the mold core.

The first sealing unit and the second sealing unit may each have a plurality of O-rings having different diameters centered on an axis extending in the longitudinal direction of the hot runner unit.

The hot runner mold of the present invention is arranged such that one side is inserted into the cooling bush for the hot runner and the other side is inserted into the mold core so that the mounting position of the cooling bush for the hot runner with respect to the cooling bush mounting groove is aligned. It may further include a pin.

According to the present invention, the shortest distance between a gate and a cooling passage formed in a cooling bush for a hot runner is shorter than the shortest distance between a gate and a path through which refrigerant flows in a conventional cooling bush for a hot runner. Therefore, the cooling and curing of the resin filled in the gate is not delayed, thereby shortening the injection molding cycle time, and preventing shrinkage of the molded product caused in the gate area due to delayed cooling of the gate and resulting product defects.

According to the present invention, the refrigerant supply line and refrigerant discharge line, which are connected to the cooling bush for the hot runner to allow inflow and outflow of the refrigerant, do not penetrate the inside of the mold core, but penetrate the disk of the mold and are connected to the cooling bush for the hot runner. do. Therefore, the gate can be cooled reliably even when the axis of the hot runner part is tilted more than the conventional hot runner part with respect to the skin surface of the cavity, increasing the design freedom of the hot runner mold and reducing bending. Plastic products with many shapes can be easily manufactured by injection molding, and productivity is improved by installing multiple hot runner parts in one hot runner mold and injection molding multiple plastic products through one molding cycle. .

According to the cooling bush for a hot runner according to a preferred embodiment of the present invention, which includes a first sealing portion in close contact with the inner flow path forming portion and the mold core, and a second sealing portion in close contact with the outer circumferential flow path forming portion and the mold core, the mold core As the clamping force of the bolt that secures the cooling bush for the hot runner increases, the sealing force of the first sealing portion and the second sealing portion increases, so that refrigerant leakage and damage to the hot runner mold resulting therefrom are reliably suppressed.

Figure 1 is a perspective view showing an upper mold belonging to a hot runner mold according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view of FIG. 1 taken along line II-II.
FIG. 3 is an enlarged view of part III of FIG. 2.
FIG. 4 is an enlarged view of part IV of FIG. 3, and FIG. 5 is an enlarged view of part V of FIG. 3.
Figures 6, 4 and 5 are perspective views showing the cooling bush of Figure 3 viewed from above, and Figure 7 is a perspective view showing the cooling bush of Figure 3 seen from below.
Figure 8 is a perspective view showing the cooling bush of Figure 3 partially cut away.

Hereinafter, a cooling bush for a hot runner and a hot runner mold equipped therewith according to an embodiment of the present invention will be described in detail with reference to the attached drawings. The terminology used in this specification is a term used to appropriately express preferred embodiments of the present invention, and may vary depending on the intention of the user or operator or the customs of the field to which the present invention belongs. Therefore, definitions of these terms should be made based on the content throughout this specification.

FIG. 1 is a perspective view showing an upper mold belonging to a hot runner mold according to an embodiment of the present invention, FIG. 2 is a cross-sectional view taken along II-II of FIG. 1, and FIG. 3 is an enlarged view of portion III of FIG. 2. 4 is an enlarged view of part IV of FIG. 3, FIG. 5 is an enlarged view of part V of FIG. 3, and FIGS. 6 and 4 are views of the cooling bush of FIG. 3 from above. FIG. 7 is a perspective view of the cooling bush of FIG. 3 viewed from below, and FIG. 8 is a perspective view of the cooling bush of FIG. 3 cut away partially.

Referring to FIGS. 1 to 3, the hot runner mold 10 includes an upper mold 11 and a lower mold 80 that move in directions approaching and moving away from each other. When the upper mold 11 and the lower mold 80 come closer and come into close contact with each other, it is called mold closing. Conversely, when the upper mold 11 and the lower mold 80 move away from each other and are spaced apart, it is called mold opening. It is said. During mold closing and mold opening, the upper mold 11 and the lower mold 80 may move together in opposite directions, or the upper mold 11 does not move and only the lower mold 80 moves relative to the upper mold 11. It may be possible.

The upper mold 11 includes a base 12, first and second disks 15 and 20, a mold core 25, a manifold 50, and a first hot runner unit. ) (51), a second hot runner portion (60), and a cooling bush (100) for the hot runner. A sprue 13 connected to a resin injection device (not shown) is formed on the base 12. The molten resin injected from the resin injection device is injected into the interior of the upper mold 11 through the sprue 13. The molten resin may be, for example, PMMA (polymethyl methacrylate), which belongs to thermoplastic resin.

The first disc 15 is fixedly supported on the base 12, and the second disc 20 is fixedly supported on the first disc 15. do. The first disk 15 has a manifold that divides and distributes the molten resin injected into the interior of the upper mold 11 through the sprue 13 into the first hot runner portion 51 and the second hot runner portion 60. A manifold 50 is installed. A core mounting groove 21 in which the mold core 25 is seated and fixed is formed in the second disk 20.

The mold core 25 is inserted and seated in the core mounting groove 21 and is fixedly supported on the second disk 20. The mold core 25 has a skin surface 26 corresponding to the upper side shape of the plastic product (not shown) to be injection molded. The skin surface 26 is provided on the lower side of the mold core 25 facing the lower mold 80. Although not shown in detail in FIG. 2, the lower mold 80 may be provided with a mold core (not shown) having a skin surface 85 corresponding to the shape of the lower side of the plastic product (not shown) to be injection molded.

When the upper mold 11 and the lower mold 80 are closed, the skin surface 26 of the upper mold 11 and the skin surface 85 of the lower mold 80 are combined to form a cavity corresponding to the complete shape of the plastic product. ) is formed. The cavity is filled with molten resin injection-injected into the upper mold (11). In other words, the skin surface 26 of the upper mold 11 defines one part of the cavity, and the skin surface 85 of the lower mold 80 defines the remaining part of the cavity.

The mold core 25 further includes a gate 28 through which the molten resin passes when injected into the cavity. A cooling bush mounting groove 30 in which the cooling bush 100 for a hot runner is seated and mounted is formed in the mold core 25. The first hot runner portion 51 and the second hot runner portion 60 extend toward the skin surface 26 through the first disk 15, the second disk 20, and the mold core 25. . Specifically, the first hot runner portion 51 extends so that its lower end is connected to a gate (not shown) connected to a point on the skin surface 26, and the molten resin flows through the first hot runner portion 51. It flows through a connected gate (not shown). The second hot runner portion 60 extends so that its lower end is connected to the gate 28 connected to another point of the skin surface 26, and the molten resin is connected to the gate (28) through the second hot runner portion 60. 28).

The first hot runner portion 51 extends parallel to the vertical direction in which the lower mold 80 moves relative to the upper mold 11 to open and close the mold. The second hot runner portion 60 is positioned to be spaced apart from the first hot runner portion 51 and extends at an angle with respect to the vertical direction in which the lower mold 80 moves with respect to the upper mold 11.

The second hot runner unit 60 includes a hot runner housing 61, a valve pin 67, a nozzle 63, and a nozzle fixture 65. The hot runner housing 61 is a hollow, cylinder-shaped member that extends from the inside of the first disk 15 across the second disk 20 to the inside of the mold core 25. The hollow of the hot runner housing 61 becomes a hot runner 66 filled with molten resin. The molten resin injected into the interior of the upper mold 11 through the sprue 13 is distributed in the manifold 50 and flows into the hot runner 66 of the second hot runner portion 60.

A heater that heats the molten resin filled in the hot runner 66 is installed on the outer peripheral surface of the hot runner housing 61 to prevent the molten resin filled in the hot runner 66 from cooling and hardening during the injection molding process of plastic products. do. The nozzle 63 is fixed to the lower end of the hot runner housing 61 by the nozzle fixture 65, and is seated on the nozzle seating surface 39 formed on the mold core 25 and connected to the gate 28. The valve pin 67 extends along the axis AX extending in the longitudinal direction of the second hot runner portion 60 so as to penetrate the hot runner 66. The upper end of the valve pin 67 is connected to an actuator (not shown) that drives the valve pin 67 to rise and fall inside the hot runner 66.

When the valve pin 67 is lowered away from the base 12 inside the hot runner 66, the valve tip 68 at the bottom of the valve pin 67 is lowered to close the hole of the nozzle 39. And, the molten resin does not flow into the gate 28 from the hot runner 66. With the upper mold 11 and the lower mold 80 closed, when the valve pin 67 rises close to the base 12 inside the hot runner 68, the hole in the nozzle 39 is opened and the hot runner (68) is closed. Molten resin is injected from 66) into the gate 28 and a cavity (not shown) connected thereto.

Although not clearly shown, the first hot runner unit 51 may also include the same hot runner housing, valve pin, nozzle, and nozzle fixture as those provided in the second hot runner unit 60. A hot runner in which the molten resin distributed from the manifold 50 flows into the hot runner housing of the first hot runner unit 51 and is maintained without cooling and hardening may be formed. In Figure 2, the first hot runner unit 51 and the second hot runner unit 60 are shown one by one, but the present invention is not limited thereto and a plurality of first hot runner units and a plurality of second hot runner units may be provided. there is.

A tubular gate cooling line (not shown) passing through the mold core 25 in the horizontal direction may be formed around the gate connected to the first hot runner unit 51. When the upper mold 11 and the lower mold 80 are closed and the molten resin is injected into the cavity through a gate (not shown) connected to the first hot runner unit 51, the refrigerant flows through the tubular gate cooling line. The molten resin filled in the gate connected to the first hot runner unit 51 can be quickly cured at a rate comparable to the molten resin filled in the cavity.

A tubular gate cooling line passing through the mold core 25 in the horizontal direction is not formed around the gate 28 connected to the second hot runner unit 60. In particular, when a plurality of second hot runner parts 60 are installed in the upper mold 11 and the nozzles 63 of the plurality of second hot runner parts 60 are not located at the same height, the mold core ( 25) Processing to form a plurality of gate cooling lines corresponding to the number of the plurality of second hot runner parts 60 inside is difficult, and the space inside the mold core 25 is insufficient. Accordingly, the hot runner mold 10 is cooled by surrounding the lower end of the first hot runner portion 60 instead of the tubular gate cooling line crossing the periphery of the gate 28 connected to the second hot runner portion 60. It is provided with a cooling bush 100 (see FIGS. 6 and 7) for a hot runner that is fixedly mounted in the bush mounting groove 30.

Referring to Figures 3 to 8, the cooling bush 100 for a hot runner includes an outer peripheral surface flow path forming part 130, an internal flow path forming part 110, a first sealing part 160, a second sealing part 165, It includes a refrigerant supply connection tube 151, and a refrigerant discharge connection tube 154. The outer circumferential flow path forming part 130 and the inner flow path forming part 110 may be formed integrally. The internal flow path forming part 110 is formed above the outer circumferential flow path forming part 130, that is, formed to be further spaced from the gate 28 than the outer circumferential flow path forming part 130. A hollow 101 extending along the axis AX is formed in the hot runner cooling bush 100 so that the lower end of the second hot runner portion 60 penetrates.

The internal flow path forming part 110 is a generally disk-shaped part centered on the axis line AX, and the outer circumferential flow path forming part 130 is connected to the bottom of the inner flow path forming part 110 and extends along the axis line AX. It is a generally cylindrical part that extends along. The diameter of the internal flow path forming part 110 is larger than the diameter of the outer circumferential flow path forming part 130. In Figure 8, the boundary between the inner flow path forming part 110 and the outer circumferential flow path forming part 130 is shown as a dotted line. The cooling bush mounting groove 30 formed in the mold core 25 is defined by the inner flow path forming portion support surface 31, the outer circumferential flow path forming portion support surface 27, and the groove inner circumferential surface 35.

The inner flow path forming portion support surface 31 is a plane that contacts and supports the lower side 111 of the inner flow path forming portion 110 and is perpendicular to the axis line AX. The outer circumferential flow path forming part support surface 37 is a surface that contacts and supports the lower end surface 133 of the outer circumferential flow path forming part 130. The groove inner circumferential surface 35 connects the inner flow path forming part support surface 31 and the outer circumferential flow path forming part support surface 37 in a stepped manner and is a surface facing the outer circumferential surface 131 of the outer circumferential flow path forming part 130.

A cooling passage 140 through which a refrigerant flows to cool and harden the molten resin filled in the gate 28 through the nozzle 63 of the second hot runner portion 60 is provided on the outer peripheral surface 131 of the outer circumferential flow path forming portion 130. is formed. The internal flow path forming portion 110 includes a refrigerant inlet flow path 120 connected to one side of the cooling flow path 140, specifically the upper end of one of the left and right sides, and a cooling flow path 140 so that the refrigerant flows into the cooling flow path 140. ), a refrigerant outflow passage 125 connected to the other side of the cooling passage 140, specifically, the upper end of the other side of the left and right sides, is formed so that the refrigerant flows out. The refrigerant may be, for example, a coolant.

The refrigerant inlet flow path 120 extends in a direction perpendicular to the axis AX within the inner flow path forming part 110 and includes a first inflow flow path part 121 on one side open to the outer peripheral surface of the flow path forming part 110. And, it is connected to the other side of the first inlet flow path portion 121 and extends parallel to the axis AX toward the outer circumferential flow path forming portion 130 to form an upper end of one side of the cooling flow path 140, specifically the first spiral flow path. It includes a second inlet flow path portion 123 connected to the upper end of the portion 141.

The refrigerant outflow passage 125 is perpendicular to the axis AX inside the internal passage forming portion 110 and extends in a direction parallel to the first inflow passage portion 121, and has one side of the outer peripheral surface of the passage forming portion 110. A first outflow flow path portion 126 opened to the other side of the first outflow flow path portion 126 extends parallel to the axis AX toward the outer circumferential flow path forming portion 130 and extends to the other side of the cooling flow path 140. It includes a second outflow flow path portion 128 connected to the top of, specifically, the top of the second spiral flow path portion 144.

The refrigerant supply connection tube 151 is coupled to the outer peripheral surface of the inner flow path forming part 110 so as to be connected to one side of the first inlet flow path portion 121, and the refrigerant discharge connection tube 154 is connected to the first outlet flow path portion 126. ) is coupled to the outer peripheral surface of the internal flow path forming portion 110 so as to be connected to one side of the.

The cooling passage 140 includes a first spiral passage portion 141, a second spiral passage portion 144, and a connection passage portion 147. The first spiral flow path portion 141 extends downward along the first spiral orbit and guides the refrigerant to flow in a direction away from the internal flow path forming portion 110.

The second spiral passage portion 144 extends downward along a second spiral orbit that does not intersect the first spiral orbit, and guides the refrigerant to flow in a direction approaching the internal passage forming portion 110. The connection passage portion 147 connects the lower end of the first spiral passage portion 141 and the lower end of the second spiral passage portion 144 to enable refrigerant flow. The connection flow path portion 147 extends along a circular arc path centered on the axis AX and is formed close to the bottom surface 133 of the outer circumferential flow path forming portion 130. Dead ends 148 are formed at both ends of the connection passage portion 147 to block the flow of refrigerant so that the connection passage portion 147 does not continue in a circle but has a circular path.

To elaborate, the first spiral flow path portion 141 and the second spiral flow path portion 144 are spiral grooves dug inward from the outer circumferential surface 131 of the outer circumferential flow path forming portion 130 and extending along helical trajectories that do not intersect each other. am. The connection passage portion 147 is dug inward from the lower end of the outer peripheral surface 131 of the outer circumferential passage forming portion 130 and is connected to the lower end of the first spiral passage portion 141 and the lower end of the second spiral passage portion 144. It is a long groove that extends along an arc path.

The hot runner mold 10 (see FIG. 2) has a refrigerant supply line (line not shown) connected to the internal flow path forming part 110 so that the refrigerant is supplied to the refrigerant inlet flow path 120 from outside the inner flow path forming part 110. ), and a refrigerant discharge line (not shown) connected to the inner flow path forming part 110 so that the refrigerant is discharged from the refrigerant outflow flow path 125 to the outside of the inner flow path forming part 110. Specifically, the refrigerant supply line is for supplying refrigerant, for example, one end is connected to the refrigerant supply connection tube 151 and the other end is connected to a refrigerant circulation supply device (not shown) located outside the hot runner mold 10. It is a hose, and the refrigerant discharge line may be, for example, a refrigerant discharge hose in which one end is connected to the refrigerant discharge connection tube 154 and the other end is connected to a refrigerant circulation supply device.

The refrigerant supply connection tube 151 and the refrigerant discharge connection tube 154 may be accommodated in the connection tube receiving groove 23 formed in the second disk 20 to be open toward the core mounting groove 21. The refrigerant supply line and the refrigerant discharge line cross the second disk 20 through the refrigerant line arrangement groove 24 formed in the second disk 20 and extend to the outside of the second disk 20 to be connected to the refrigerant circulation supply device. It is extended. The refrigerant line arrangement groove 24 extends along the refrigerant supply line and the refrigerant discharge line, has one longitudinal side connected to the connection tube receiving groove 23, and is open toward the first disk 15.

The upper mold 11 and the lower mold 80 are closed and the gate 28 and the cavity are filled with molten resin through the first and second hot runner parts 51 and 60, and the cavity and the gate are cooled almost simultaneously. It goes on. The gate 28 connected to the second hot runner unit 60 includes a refrigerant supply line (not shown), a refrigerant supply connection tube 151, a first inlet flow path 121, a second inlet flow path 123, First spiral flow path part 141, connection flow path part 147, second spiral flow path part 144, second outflow flow path part 128, first outflow flow path part 126, refrigerant discharge connection tube 154 It is cooled by the refrigerant that sequentially flows through , and the refrigerant discharge line (not shown) and exchanges heat with the gate 28 in the cooling line 140, especially the connection passage portion 147. The molten resin filled in the gate 28 is rapidly cooled and hardened at approximately the same rate as the molten resin filled in the cavity, so that defects due to shrinkage of the molded product in the surrounding area of the gate 28 are suppressed.

The refrigerant supply line and the refrigerant discharge line, that is, the refrigerant supply hose and the refrigerant discharge hose, the refrigerant supply connection tube 151, and the refrigerant discharge connection tube 154 are connected to the first disk 15, the second disk 20, And since heat loss through heat exchange is minimized by being spaced apart from the mold core 25, the cooling efficiency of the gate 28 by the refrigerant flowing along the cooling passage 140 is improved. In other words, the molten resin filling the gate 28 can be cooled and hardened more quickly. The flow of refrigerant through the cooling passage 140 may be illustrated by arrows shown in FIGS. 6 and 7 . In other words, the refrigerant flows from the top to the bottom of the outer circumferential flow path forming part 130 through the first spiral flow path part 141, and the refrigerant flows from below the outer circumferential flow path forming part 130 through the second spiral flow path part 144. Flowing upward, the refrigerant can flow at the same height along the axis AX through the connection passage portion 147.

Since the cooling flow path 140 is formed on the outer circumferential surface rather than the inside of the outer circumferential flow path forming part 130, the diameter of the outer circumferential flow path forming part 130 can be designed to be small, so that the lower peripheral portion of the outer circumferential flow path forming part 130 The angle AT between the axis line AX and an imaginary line connecting the valve tip 68 may be narrowed to, for example, 40 to 50°. In addition, a cooling line passing through the mold core 25 in the horizontal direction is not provided between the lower outer circumference of the outer circumferential flow passage forming portion 130 and the skin surface 26. Therefore, the skin surface 26 can be designed to be more curved than before so that plastic products with greater curves can be molded, and the hot runner has the axis line AX inclined as shown in Figures 2 and 3. Unit 60 may also be installed.

In FIG. 3 , the distance DS between the lowest end of the cooling passage 140, that is, the lowest end of the connection passage portion 147, and the gate 28 may be narrowed to, for example, 9 to 13 mm. Therefore, even if a cooling line penetrating the mold core 25 in the horizontal direction is not provided between the lower outer circumference of the outer circumferential flow path forming portion 130 and the skin surface 26, cooling of the molten resin filled in the gate 28 is possible. There is no delay.

The first sealing portion 160 is located at the upper end of the cooling passage 140 along the longitudinal direction of the second hot runner portion 60, that is, the axis AX, that is, the first spiral passage portion 141 and the second spiral passage portion. It is in close contact with the internal flow path forming part 110 and the mold core 25 at a position higher than the top of the part 144 to prevent leakage of the refrigerant. The second sealing portion 165 is positioned along the longitudinal direction of the second hot runner portion 60, that is, along the axis AX, at a lower position than the bottom of the cooling passage 140, that is, the lower end of the connection passage portion 147. It is in close contact with the outer circumferential flow path forming portion 130 and the mold core 25 to prevent leakage of refrigerant.

The first seal 160 and the second seal 165 each have a plurality of O-rings 161, 163 centered on the axis AX and extending along circular orbits with different diameters. , 166, 168). The plurality of O-rings 161, 163, 166, and 168 may be made of a rubber material. To elaborate, the first sealing part 160 includes a first upper O-ring 161 and a second upper O-ring 163 having a diameter smaller than the diameter of the first upper O-ring 161. A first upper O-ring mounting groove 117 on which the first upper O-ring 161 is mounted is formed on the lower side 111 of the internal flow path forming portion 110, and the inner flow path forming portion of the mold core 25 A second upper O-ring mounting groove 41 on which the second upper O-ring 163 is mounted is formed on the support surface 31.

The second seal 165 includes a first lower O-ring 166 and a second lower O-ring 168 having a diameter smaller than the diameter of the first lower O-ring 166. A first lower O-ring mounting groove 136 on which the first lower O-ring 166 is mounted is formed on the lower surface 133 of the outer circumferential flow path forming portion 130, and the outer circumferential flow path forming portion support surface of the mold core 25 ( 37), a second lower O-ring mounting groove 43 on which the second lower O-ring 168 is mounted is formed.

The cooling bush 100 for a hot runner is seated in the cooling bush mounting groove 30 and is fixed to the mold core 25 by a plurality of bolts (not shown). To elaborate, a plurality of bolt fastening holes 113 penetrating the internal flow path forming part 110 are formed in parallel with the axis AX to allow a plurality of bolts to pass through, and a plurality of bolt fastening holes 113 are formed in the internal flow path forming part 110, The cooling bush 100 for hot runner is fixed to the mold core 25 by penetrating each of the plurality of bolt fastening holes 113 and being driven into the internal flow path forming portion support surface 31.

At this time, as the clamping force of the plurality of bolts increases, the plurality of O-rings 161 and 163 of the first sealing part 160 form the lower side 111 of the internal flow forming part 110 and the internal flow path of the mold core 25. It is in close contact with the secondary support surface 31 with a stronger force, and the plurality of O-rings 166 and 168 of the second sealing part 165 are connected to the lower surface 133 of the outer circumferential flow path forming part 130 and the mold core 25. The outer peripheral surface of the flow path forming portion is adhered to the support surface 37 with a stronger force. Due to this, leakage of refrigerant between the cooling bush 100 for the hot runner and the mold core 25 is reliably prevented.

When mounting the hot runner cooling bush 100 on the cooling bush mounting groove 30, the hot runner mold 10 aligns the mounting position of the hot runner cooling bush 100 with respect to the cooling bush mounting groove 30. , It further includes a plurality of alignment pins 170 to prevent minute rotation of the hot runner cooling bush 100 about the axis AX after the hot runner cooling bush 100 is mounted. . The plurality of alignment pins 170 extend parallel to the axis line AX and have one side fitted into the hot runner cooling bush 100 and the other side fitted into the mold core 25.

Specifically, a plurality of alignment pin upper holes 115 into which the upper portions of the plurality of alignment pins 170 are inserted are formed on the lower side 111 of the internal flow path forming portion 110, and the mold core 25 A plurality of alignment pin lower holes 33 into which lower portions of the plurality of alignment pins 170 are inserted are formed on the support surface 31 of the internal flow path forming portion. The plurality of alignment pin upper holes 115 and the plurality of alignment pin lower holes 33 may be aligned to overlap top and bottom.

According to the hot runner mold 10 described above, the shortest distance DS between the cooling passage 140 formed in the hot runner cooling bush 100 and the gate 28 is the refrigerant in the conventional hot runner cooling bush. It is shorter than the shortest distance between the flowing path and the gate. Therefore, the cooling hardening of the resin filled in the gate 28 is not delayed, thereby shortening the cycle time of injection molding, and the delayed cooling of the gate 28 causes shrinkage of the molded product caused in the gate 28 portion. Product defects due to this are prevented.

In addition, the refrigerant supply line and refrigerant discharge line that are connected to the cooling bush 100 for the hot runner to enable inflow and outflow of the refrigerant do not penetrate the inside of the mold core 25, but are formed on the second disk of the hot runner mold 10. It passes through (20) and is connected to the cooling bush 100 for the hot runner. Therefore, the gate 28 can be cooled reliably even when the axis AX of the hot runner unit 60 is inclined more than in the case of a conventional hot runner unit with respect to the skin surface 26 of the cavity, thereby preventing the hot runner unit 60 from being reliably cooled. The design freedom of the runner mold 10 increases, plastic products with many curved shapes can be easily manufactured by injection molding, and multiple hot runner parts 51 and 60 are installed in one hot runner mold 10. By installing a , productivity is improved by injection molding multiple plastic products through one molding cycle.

The cooling bush 100 for hot runs increases as the clamping force of the bolts that secure the cooling bush 100 for hot runners to the mold core increases, the sealing force of the first sealing part 160 and the second sealing part 165 increases, so the refrigerant Leakage and damage to the hot runner mold 100 resulting therefrom are reliably suppressed.

The present invention has been described with reference to an embodiment shown in the drawings, but this is merely illustrative, and those skilled in the art will recognize that various modifications and other equivalent embodiments are possible therefrom. You will understand. Therefore, the true scope of protection of the present invention should be determined only by the appended claims.

10: Hot runner mold 11: Upper mold
15, 20: first and second disks 21: core mounting groove
25: Mold core 51: First hot runner portion
60: second hot runner part 65: nozzle
80: Lower mold 100: Cooling bush for hot runner
110: internal flow path forming part 120: refrigerant inlet flow path
125: Refrigerant outflow flow path 130: Outer peripheral surface flow path forming part
140: cooling flow path 141: first spiral flow path part
144: second spiral flow path part 147: connection flow path part
160: first sealing portion 165: second sealing portion

Claims (12)

An outer circumferential flow path forming portion formed on the outer circumferential surface through which a refrigerant that cools and hardens the molten resin filled in the gate flows through the hot runner portion connected to the gate of the mold core; and
An internal flow path forming portion having a refrigerant inlet flow path connected to one side of the cooling flow path to allow the refrigerant to flow into the cooling flow path, and a refrigerant outlet flow path connected to the other side of the cooling flow path to allow the refrigerant to flow out of the cooling flow path. A cooling bush for a hot runner, comprising:
According to claim 1,
The cooling passage is,
a first spiral flow path portion whose one end is connected to the refrigerant inflow path and guides the refrigerant to flow in a direction away from the internal flow path forming portion along a first spiral trajectory;
a second spiral flow path portion whose one end is connected to the refrigerant outlet flow path and which guides the refrigerant to flow in a direction approaching the internal flow path forming portion along a second spiral trajectory that does not intersect the first spiral trajectory; and
A cooling bush for a hot runner, comprising: a connection passage portion connecting the other end of the first spiral passage portion and the other end of the second spiral passage portion to enable refrigerant flow.
According to clause 2,
The cooling bush for a hot runner, wherein the connection passage portion extends along an arc path centered on an axis extending in the longitudinal direction of the hot runner portion.
According to claim 1,
a first sealing part that is in close contact with the inner flow path forming part and the mold core at a position higher than the top of the cooling flow path along the longitudinal direction of the hot runner part to prevent leakage of the refrigerant; and
A second sealing part that is in close contact with the outer circumferential flow path forming part and the mold core at a position lower than the bottom of the cooling flow path along the longitudinal direction of the hot runner part and prevents leakage of the refrigerant. Characterized in that it further comprises a. Cooling bush for hot runners.
a mold core having a skin surface defining a cavity, a gate through which molten resin passes when injected into the cavity, and formed with a cooling bush mounting groove;
A disk that fixedly supports the mold core;
A hot runner extends from the inside of the disk and the mold core toward the gate, has a hot runner formed therein, and is connected to the gate so that the molten resin flows from the hot runner to the gate. Runner part; and
It is mounted on the cooling bush mounting groove and has a cooling passage formed on the outer peripheral surface through which a refrigerant that cools and hardens the molten resin filled in the gate through the hot runner portion is formed, and the refrigerant flows into the cooling passage. Cooling for a hot runner, including a refrigerant inflow passage connected to one side of the cooling passage as much as possible, and an internal passage forming portion formed therein with a refrigerant outflow passage connected to the other side of the cooling passage to allow the refrigerant to flow out of the cooling passage. A hot runner mold comprising a bush.
According to clause 5,
The cooling passage is,
a first spiral flow path portion whose one end is connected to the refrigerant inflow path and guides the refrigerant to flow in a direction away from the internal flow path forming portion along a first spiral trajectory;
a second spiral flow path portion whose one end is connected to the refrigerant outlet flow path and which guides the refrigerant to flow in a direction approaching the internal flow path forming portion along a second spiral trajectory that does not intersect the first spiral trajectory; and
A hot runner mold comprising: a connection passage portion connecting the other end of the first spiral passage portion and the other end of the second spiral passage portion to enable refrigerant flow.
According to clause 6,
A hot runner mold, wherein the connection passage portion extends along an arc path centered on an axis extending in the longitudinal direction of the hot runner portion.
According to clause 5,
a refrigerant supply line connected to the internal flow path forming part so that the refrigerant is supplied to the refrigerant inlet flow path outside the internal flow path forming part; and
It further includes a refrigerant discharge line connected to the internal flow path forming part so that the refrigerant is discharged from the refrigerant outlet flow path to the outside of the internal flow path forming part,
A hot runner mold, characterized in that the coolant supply line and the coolant discharge line extend outwardly from the disk across the disk through a coolant line arrangement groove formed in the disk.
According to clause 5,
The cooling bush for the hot runner includes a first sealing part that is in close contact with the inner flow path forming part and the mold core at a higher position than the top of the cooling flow path along the longitudinal direction of the hot runner part to prevent leakage of the refrigerant, And a second sealing part that is in close contact with the outer circumferential flow path forming part and the mold core at a position lower than the bottom of the cooling flow path along the longitudinal direction of the hot runner part to prevent leakage of the refrigerant. hot runner mold.
According to clause 9,
The internal flow path forming portion and the mold core are fastened with bolts,
As the clamping force of the bolt increases, the first sealing part comes into closer contact with the inner flow path forming part and the mold core, and the second sealing part comes into closer contact with the outer circumferential flow path forming part and the mold core. hot runner mold.
According to clause 9,
The first sealing portion and the second sealing portion are each centered on an axis extending in the longitudinal direction of the hot runner portion and include a plurality of O-rings having different diameters. mold.
According to clause 5,
It further includes an alignment pin, one side of which is inserted into the hot runner cooling bush and the other side of which is inserted into the mold core, so that the mounting position of the hot runner cooling bush with respect to the cooling bush mounting groove is aligned. A hot runner mold characterized in that.

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