JP3205019U - Sprue bush - Google Patents

Abstract

A sprue bush is provided that can suppress the temperature drop of molten resin injected into a mold as much as possible even when injecting a resin with an extremely short injection time. A sprue bushing S1 for injecting molten resin into a mold K, which is attached to the mold K and has a housing hole 1 formed along the injection direction of the molten resin inside. And a flow path member 4 that is mounted in the accommodation hole 1 of the sprue body 2 and has a flow path 3 in which a molten resin flows therein. The thermal conductivity of the flow path member 4 is greater than the thermal conductivity of the sprue body 2. Is also small. The flow path member 4 has a nozzle touch portion 4a against which a nozzle N that injects molten resin is pressed. The material of the sprue body 2 is carbon steel, and the material of the flow path member 4 is titanium or zirconia having a lower thermal conductivity than that of carbon steel. [Selection] Figure 4

Description

  The present invention relates to a sprue bush for injecting a molten resin (hereinafter referred to as a molten resin) into a mold.

  As shown in FIG. 1, a sprue bush S for injecting molten resin into the mold K is attached to a mold K used for resin injection molding. The sprue bush S is for injecting the molten resin into the mold K by injecting the molten resin from the nozzle N in a state where the injection nozzle N is pressed.

  The molten resin injected into the mold K from the sprue bush S is filled into the cavity C through the runner recess R and the pinpoint gate bush P formed in the mold K. After the molten resin filled in the cavity C cools and hardens, the mold K is opened, the runner is discharged from the runner recess R, and the molded product is taken out from the cavity C. Thereafter, the mold 1 is closed, and a cycle of injecting molten resin into the mold K from the nozzle N via the sprue bush S is repeated.

  As the sprue bush S used for such injection molding, the present inventor first developed a sprue bush SJ as shown in FIG. 2 (see Patent Document 1). The sprue bushing SJ includes a metal channel member 12 having a molten resin channel 11 formed therein, and a heat insulation formed in a ring shape along the longitudinal direction of the channel 11 on the outer periphery of the channel member 12. A layer 13 and a metal sprue body 14 provided so as to cover the heat insulating layer 13 are provided. The sprue bush SJ is injected from the nozzle N in a state where the sprue body 14 is mounted on the mold K shown in FIG. 1 and the injection nozzle N is pressed against the nozzle touch part 15 formed at the inlet of the flow path 11. The molten resin is guided into the mold K through the flow path 11.

  In the sprue bushing SJ, a flow path member 12 having a molten resin flow path 11 formed therein is thermally insulated from the sprue body 14 by a heat insulating layer 13, and the heat capacity of the flow path member 12 is thermally increased from the sprue body 14. It is blocked and limited. For this reason, when the resin is injected into the mold K, the flow path member 12 is heated in a short time by the molten resin flowing through the flow path 11, and the high fluidity is maintained while the molten resin is kept at a high temperature. Is injected into the mold K. Therefore, problems such as short shots and weld lines occurring in the molded product can be suppressed.

Japanese Patent No. 5124743

  By the way, in the sprue bushing SJ described above, the metal channel member 12 is surely thermally insulated from the sprue body 14 by the heat insulating layer 13, but the channel member 12 is formed by the molten resin flowing through the channel 11. Until the heat capacity is fully heated, the temperature of the molten resin flowing through the flow path 11 is inevitably lowered. For this reason, in the injection molding of a resin with an extremely short injection time, the injection of the resin is finished before the flow path member 12 is heated to its full heat capacity. As a result, the resin having a low temperature is put in the mold K. There is a possibility that defects such as short shots and weld lines occur in the molded product.

  For example, when so-called engineering plastics (LCP, PPS, PEEK, PES, etc.) are injection molded, engineering plastics have high heat resistance and a higher solidification temperature than ordinary plastics, so it is necessary to complete injection before solidification The injection time is extremely short (about 1/100 second to 5/100 second). In such an extremely short injection time, since the injection of the resin is completed before the flow path member 12 is heated to its full heat capacity, only the resin whose temperature is reduced by radiating heat to the flow path member 12 is a mold. It will be injected into K, and the molded product may have problems such as short shots and weld lines.

  FIG. 3 shows the relationship between the resin temperature at the outlet 16 of the flow path 11 and time when the molten resin is injected using the sprue bushing SJ described above (simulation). The temperature of the molten resin at the inlet 17 of the flow path 11 is 220 degrees Celsius. As shown in FIG. 3, the resin temperature at the outlet 16 of the flow path 11 is as low as about 120 degrees immediately after the start of injection (0 seconds), and rises to about 160 degrees, which is the maximum temperature after about one second. doing. It can be considered that this is because it takes about 1 second from the start of injection until the flow path member 12 is heated to the full heat capacity.

  Therefore, using this sprue bushing SJ, if an engineering plastic with an extremely short injection time of about 1/100 seconds to 5/100 seconds is injection-molded as described above, before the resin reaches the maximum temperature (flow path The injection is terminated (before the member 12 is heated to full heat capacity) and there is no effect of providing the heat insulating layer 13. That is, when injection molding a resin having an extremely short injection time (for example, engineering plastics), the temperature of the molten resin injected into the mold K is lowered, and the molded product may have problems such as short shots and weld lines. .

  The purpose of the present invention, which was created in view of the above circumstances, is to suppress the temperature drop of the molten resin injected into the mold as much as possible even when injecting resin with an extremely short injection time. The object is to provide a sprue bush that can be used.

  According to the present invention created to achieve the above object, a sprue bush for injecting a molten resin into a mold, which is mounted on the mold and has a receiving hole along the injection direction of the molten resin inside. A sprue body formed in the housing hole of the sprue body and having a flow path member formed therein with a flow path through which a molten resin flows, the thermal conductivity of the flow path member being the thermal conductivity of the sprue body A sprue bush is provided which is characterized by being smaller.

  In the sprue bush according to the present invention, the flow path member may have a nozzle touch portion to which a nozzle for injecting molten resin is pressed.

  In the sprue bush according to the present invention, the material of the sprue body may be carbon steel, and the material of the flow path member may be titanium or zirconia having a thermal conductivity smaller than that of carbon steel.

  In the sprue bush according to the present invention, the flow path member includes a nozzle touch member to which a nozzle for injecting a molten resin is pressed, and a flow path body member disposed adjacent to the nozzle touch member, and the heat of the nozzle touch member. The conductivity may be smaller than the thermal conductivity of the flow path body member.

  In the sprue bush according to the present invention, the material of the sprue body is carbon steel, the material of the flow path body member is titanium having a lower thermal conductivity than that of carbon steel, and the material of the nozzle touch member is more thermally conductive than titanium. Zirconia with a small rate may be used.

The sprue bush according to the present invention can exhibit the following effects.
(1) A sprue bush according to the present invention has a sprue body mounted on a mold and a flow channel member mounted on the sprue body, and the thermal conductivity of the flow channel member is greater than the thermal conductivity of the sprue body. Is also small. As a result, the molten resin flowing through the flow path formed inside the flow path member is insulated from the sprue body having a high thermal conductivity by the flow path member having a low thermal conductivity. Therefore, the molten resin flowing through the flow path of the flow path member can suppress heat radiation to the mold via the sprue body immediately after flowing into the flow path. Therefore, even when a resin (for example, engineering plastic) having a very short injection time is injected, a temperature drop of the molten resin injected into the mold can be suppressed as much as possible.
(2) Since this sprue bushing has a structure in which a channel member having a low thermal conductivity is mounted in the accommodation hole of the sprue body having a high thermal conductivity, for example, compared to a case where a heat insulating layer is coated on the inner surface of the channel. Easy to manufacture and excellent in productivity.

It is sectional drawing of the metal mold | die with which the sprue bush was mounted | worn. It is explanatory drawing of the sprue bush which concerns on the comparative example (not embodiment) of this invention, (a) is a top view, (b) is side sectional drawing, (c) is XX sectional drawing of (b). It is. It is a graph which shows the resin injection temperature of the sprue bush which concerns on a comparative example. It is explanatory drawing of the sprue bush which concerns on one Embodiment of this invention, (a) is a top view, (b) is a sectional side view, (c) is the YY sectional view taken on the line of (b). It is a graph which shows the resin injection temperature of the sprue bush which concerns on the said embodiment. It is explanatory drawing of the sprue bush which concerns on deformation | transformation embodiment of this invention, (a) is a top view, (b) is a sectional side view, (c) is the sectional view on the ZZ line of (b).

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the present specification and drawings, elements having substantially the same functions and configurations are denoted by the same reference numerals, and redundant description is omitted, and elements not directly related to the present invention are not shown. To do.

(Mold K)
As shown in FIG. 1, a sprue bush S <b> 1 for injecting molten resin into the mold K is attached to the mold K used for resin injection molding instead of the sprue bush S. The sprue bush S1 injects the molten resin into the mold K by injecting the molten resin from the nozzle N in a state where the injection nozzle N is pressed.

  The molten resin injected into the mold K from the sprue bush S1 is filled into the cavity C through the runner recess R and the pinpoint gate bush P formed in the mold K. After the molten resin filled in the cavity C cools and hardens, the mold K is opened, the runner is discharged from the runner recess R, and the molded product is taken out from the cavity C. Thereafter, the mold 1 is closed, and a cycle of injecting molten resin into the mold K from the nozzle N via the sprue bush S is repeated.

(Outline of sprue bushing S1)
As shown in FIG. 4, a sprue bushing S1 according to an embodiment of the present invention includes a sprue body 2 that is mounted on a mold K and has a housing hole 1 formed along the injection direction of the molten resin. And a flow path member 4 that is mounted in the housing hole 1 of the body 2 and has a flow path 3 in which a molten resin flows therein. The thermal conductivity of the flow path member 4 is smaller than the thermal conductivity of the sprue body 2. It is characterized by that. Hereinafter, each component of the sprue bushing S1 according to the present embodiment will be described.

(Sprue body 2)
As shown in FIG. 4, the sprue body 2 includes a flange portion 2a and a cylindrical portion 2b, and is attached to the mold K shown in FIG. 1, and is fixed to the mold K by bolts or screws (not shown). . The sprue body 2 is made of carbon steel such as SKD61. An accommodation hole 1 is formed in the center of the flange portion 2a and the cylindrical portion 2b of the sprue body 2 along the injection direction of the molten resin. The accommodation hole 1 includes a large-diameter hole 1a formed in the flange portion 2a and a small-diameter hole 1b formed in the cylindrical portion 2b so as to be connected thereto. A flow path member 4 is mounted in the accommodation hole 1.

(Flow path member 4)
As shown in FIG. 4, the flow path member 4 includes a flange-shaped nozzle touch portion 4 a that engages with the large-diameter hole 1 a of the accommodation hole 1 and a cylindrical flow path that engages with the small-diameter hole 1 b of the accommodation hole 1. The main body portion 4b is integrally formed and is mounted in the accommodation hole 1 by an adhesive applied to the lower surface of the nozzle touch portion 4a. On the outer edge and the inner edge of the contact portion between the lower surface of the nozzle touch portion 4a and the bottom surface of the large-diameter hole 1a, a gap 5 for accommodating an excess adhesive is formed. A recess 6 corresponding to the shape of the nozzle N is formed on the upper surface of the nozzle touch portion 4a at a portion where the injection nozzle N shown in FIG. At the center of the flow path member 4, a flow path 3 through which the molten resin flows is formed.

(Thermal conductivity)
The thermal conductivity of the flow path member 4 is smaller than the thermal conductivity of the sprue body 2. Specifically, in this embodiment, carbon steel (SKD61 or the like) is used for the sprue body 2, and titanium (64 titanium or the like) is used for the flow path member 4. The thermal conductivity of 64 titanium is 7.5 (W / (m · K)), and the thermal conductivity of SKD61 is 29 (W / (m · K)). Note that zirconia (zirconium dioxide or the like) may be used for the flow path member 4 instead of titanium. The thermal conductivity of zirconia is 3 (W / (m · K)). The material of the channel member 4 and the material of the sprue body 2 are not limited to those described above, and various materials can be used as long as the thermal conductivity satisfies “channel member 4” <“sprue body 2”. Can do.

(Action / Effect)
As shown in FIG. 4, the sprue bushing S <b> 1 according to the present embodiment includes a sprue body 2 attached to the mold K and a flow path member 4 mounted in the sprue body 2. Is smaller than the thermal conductivity of the sprue body 2. As a result, the molten resin flowing in the flow path 3 formed inside the flow path member 4 is insulatively insulated from the sprue body 2 having a high thermal conductivity by the flow path member 4 having a low thermal conductivity. . Therefore, the molten resin flowing through the flow path 3 of the flow path member 4 can be prevented from releasing heat to the mold K via the sprue body 2 immediately after flowing into the flow path 3. Therefore, even when a resin (for example, engineering plastic) having an extremely short injection time is injected, the temperature drop of the molten resin injected into the mold K can be suppressed as much as possible.

  FIG. 5 shows the relationship between the resin temperature and the time at the outlet 17 of the flow path 3 when a molten resin is injected using the sprue bush S1 according to the present embodiment (simulation). The temperature of the molten resin at the inlet 17 of the flow path 3 is 220 degrees Celsius. As shown in FIG. 5, the resin temperature at the outlet 16 of the flow path 3 is about 155 degrees immediately after the start of injection (0 seconds), and is higher than the temperature of the comparative example (about 120 degrees) in FIG. This is because the molten resin passing through the flow path 3 is insulated from the sprue body 2 by the flow path member 4 having a thermal conductivity smaller than that of the sprue body 2, and the heat of the molten resin passes through the sprue body 2 to the mold K. This is because the heat insulation effect can be exerted immediately after the molten resin flows into the flow path 3.

  More specifically, in the comparative example shown in FIGS. 2 and 3, the heat of the molten resin in the flow path 11 is taken away by the flow path member 12 until the flow path member 12 is heated to its full heat capacity. In the meantime, the resin temperature at the channel outlet 16 becomes lower than that in the present embodiment. For this reason, when an engineering plastic (LCP, PPS, PEEK, PES, etc.) having an injection time as short as about 1/100 to 5/100 seconds is injected, the injection is performed before the flow path member 12 is heated to the full heat capacity. As a result, the temperature of the molten resin injected into the mold K is lowered, and a defect such as a short shot or a weld line may occur in the molded product.

  On the other hand, in the present embodiment shown in FIGS. 4 and 5, since the flow path member 4 in which the flow path 3 is formed functions as a heat insulating member for the sprue body 2, immediately after the molten resin flows into the flow path 3. The molten resin is insulated from the sprue body 2 and the resin temperature at the flow path outlet 16 immediately after the start of injection (0 seconds) is higher than that of the comparative example. Therefore, even when engineering plastics (LCP, PPS, PEEK, PES, etc.) with an extremely short injection time of about 1/100 seconds to 5/100 seconds are injected, a molten resin having a temperature higher than that of the comparative example is used. It can be injected into the mold K, and the occurrence of problems such as short shots and weld lines in the molded product can be suppressed.

  Further, as shown in FIG. 4, the sprue bush S1 according to the present embodiment has a nozzle touch part 4a formed integrally with a flow path member 4 (titanium), and the injection nozzle N shown in FIG. The thermal conductivity of the nozzle touch part 4a (titanium) is smaller than the thermal conductivity of the sprue body 2 (carbon steel). Therefore, the nozzle touch part 4a functions as a heat insulating member for the injection nozzle N, and the temperature decrease of the nozzle N can be suppressed. Therefore, the temperature decrease of the molten resin injected from the nozzle N to the sprue bush S1 can be suppressed. For this reason, the temperature drop of the molten resin injected into the mold K from the nozzle N via the sprue bush S1 can be suppressed as much as possible, and problems such as short shots and weld lines of the molded product can be suppressed.

  Further, the sprue bush S1 according to the present embodiment has a structure (two-piece structure) in which the flow path member 4 having a low thermal conductivity is mounted in the accommodation hole 1 in the sprue body 2 having a high thermal conductivity. Compared with the case where the inner peripheral surface of the path 3 is coated with a heat insulating layer, it is easier to manufacture and is excellent in productivity. In practice, it is difficult to coat the inner peripheral surface of the flow passage 3 (inner diameter of about 1.5 mm to 2.0 mm) of the sprue bushing S1 with high accuracy, and even if possible, the manufacturing cost Will be very expensive. On the other hand, since the sprue bushing S1 of the present embodiment has a structure in which the flow path member 4 having a low thermal conductivity is mounted in the accommodation hole 1 of the sprue body 2 having a high thermal conductivity, both heat insulation and productivity can be achieved, and the cost can be reduced. High performance.

(Modified embodiment)
FIG. 6 shows a sprue bushing S2 according to a modified embodiment of the present invention. In the sprue bush S2 according to this modified embodiment, the flow path member 4 includes a nozzle touch member 18 to which a nozzle N for injecting molten resin is pressed, and a flow path body member 19 disposed adjacent to the nozzle touch member 18. It consists of parts, and the point which the heat conductivity of the nozzle touch member 18 is smaller than the heat conductivity of the flow-path main body member 19 differs from previous embodiment, and others have the structure similar to previous embodiment. Therefore, the same components as those of the previous embodiment are denoted by the same reference numerals and description thereof is omitted, and only the nozzle touch member 18 and the flow path body member 19 which are different points will be described.

(Flow path body member 19)
As shown in FIG. 6, the flow path body member 19 includes a flange-shaped upper portion 19 a that engages with the large-diameter hole 1 a of the accommodation hole 1, and a columnar lower portion 19 b that engages with the small-diameter hole 1 b of the accommodation hole 1. Are integrally formed. At the center of the flow path main body member 19, a flow path 3 of molten resin is formed. The flow path main body member 19 is attached to the accommodation hole 1 by an adhesive applied to the lower surface of the upper portion 19a. On the outer edge and the inner edge of the contact portion between the lower surface of the upper portion 19a and the bottom surface of the large-diameter hole 1a, a gap 5 for accommodating an extra adhesive is formed. A nozzle touch member 18 is mounted on the upper surface of the upper portion 19 a of the flow path body member 19.

(Nozzle touch member 18)
As shown in FIG. 6, the nozzle touch member 18 is formed in a columnar shape that engages with the large-diameter hole 1 a of the accommodation hole 1. On the upper surface of the nozzle touch member 18, a recess 6 corresponding to the shape of the nozzle N is formed in a portion where the injection nozzle N shown in FIG. 1 is pressed. At the center of the nozzle touch member 18, the flow path 3 through which the molten resin flows is formed so as to be connected to the flow path 3 of the flow path main body member 19. The nozzle touch member 18 is attached to the upper surface of the flow path body member 19 with an adhesive. On the upper surface of the flow path main body member 19, a recess 20 for accommodating an excess adhesive is formed in a ring shape.

(Thermal conductivity)
In the sprue bush S2 according to this modified embodiment, the thermal conductivity of the flow channel body member 19 is smaller than the thermal conductivity of the sprue body 2, and the heat of the nozzle touch member 18 is lower than the thermal conductivity of the flow channel body member 19. Low conductivity. Specifically, the sprue body 2 is carbon steel (SKD61 or the like), the flow path body member 19 is titanium (64 titanium or the like) having a lower thermal conductivity than the carbon steel, and the nozzle touch member 18 is more than titanium. It is zirconia (zirconium dioxide etc.) with small heat conductivity. The thermal conductivity of SKD61 is 29 (W / (m · K)), the thermal conductivity of 64 titanium is 7.5 (W / (m · K)), and the thermal conductivity of zirconia is 3 (W / (m · K). K)). The material of the nozzle touch member 18, the flow channel body member 19, and the sprue body 2 is not limited to those described above, and the thermal conductivity is “nozzle touch member 18” <“flow channel body member 19” <“spru body. If “2” is satisfied, various materials can be used.

(Action / Effect)
As shown in FIG. 6, the sprue bush S2 according to the modified embodiment includes a sprue body 2 attached to the mold K and a flow path member 4 mounted in the sprue body 2. The nozzle touch member 18 and the flow path body member 19 are configured, and the thermal conductivity is in the relationship of “nozzle touch member 18” <“flow path body member 19” <“spru body 2”.

  Since the thermal conductivity of the channel member 4 (the nozzle touch member 18 and the channel body member 19) is smaller than the thermal conductivity of the sprue body 2, the molten resin flowing in the channel 3 formed inside the channel member 4 Is insulated from the sprue body 2 having a high thermal conductivity by the flow path member 4 having a low thermal conductivity. Therefore, the molten resin flowing through the flow path 3 of the flow path member 4 can be prevented from releasing heat to the mold K via the sprue body 2 immediately after flowing into the flow path 3. Therefore, even when a resin (for example, engineering plastic) having an extremely short injection time is injected, the temperature drop of the molten resin injected into the mold K can be suppressed as much as possible.

  Since the flow path member 4 includes a nozzle touch member 18 and a flow path body member 19 which is a separate component, and the thermal conductivity of the nozzle touch member 18 is smaller than the thermal conductivity of the flow path body member 19, the nozzle touch member Compared to the previous embodiment (see FIG. 4) in which the thermal conductivity of 18 is equal to the thermal conductivity of the flow path body member 19, the temperature drop of the injection nozzle N pressed against the nozzle touch member 18 can be suppressed. The temperature drop of the molten resin injected into the bush S2 can be suppressed. As a result, the temperature drop of the molten resin injected into the mold K can be further suppressed, and problems such as short shots and weld lines of the molded product can be further suppressed.

  By adhering the nozzle touch member 18 to the upper surface of the flow path body member 19, an extra adhesive (for example, an epoxy resin system) is formed in at least a part of the space in the recess 20 formed on the upper surface of the flow path body member 19. The thermosetting adhesive) is housed. Here, the concave portion 20 is formed in a ring shape (donut shape) so as to surround the flow path 3, and the adhesive accommodated in the concave portion 20 functions as a resin heat insulating layer, and a portion of air in the concave portion 20. Functions as an air insulation layer. Therefore, the heat insulation function for the nozzle N is improved. In addition, since the basic operations and effects of this modified embodiment are the same as those of the previous embodiment, the description thereof is omitted.

  The preferred embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the above-described embodiments, and various types within the scope described in the claims of the utility model registration. It goes without saying that any modification or modification of the above belongs to the technical scope of the present invention.

  The present invention can be used for a sprue bush for injecting molten resin into a mold.

S1 Sprue bush 1 Housing hole 2 Sprue body 3 Channel 4 Channel member 4a Nozzle touch part 4b Channel body K Mold N Nozzle S2 Sprue bush 18 Nozzle touch member 19 Channel body member

Claims (5)

A sprue bush for injecting molten resin into a mold,
A sprue body that is mounted on a mold and in which an accommodation hole is formed along the injection direction of the molten resin,
A flow path member that is mounted in the accommodation hole of the sprue body and has a flow path through which a molten resin flows;
The thermal conductivity of the flow path member is smaller than the thermal conductivity of the sprue body,
Sprue bush characterized by that.   The sprue bush according to claim 1, wherein the flow path member has a nozzle touch portion to which a nozzle for injecting molten resin is pressed.   The sprue bush according to claim 1 or 2, wherein a material of the sprue body is carbon steel, and a material of the flow path member is titanium or zirconia having a thermal conductivity smaller than that of carbon steel.   The flow path member includes a nozzle touch member to which a nozzle for injecting a molten resin is pressed, and a flow path body member disposed adjacent to the nozzle touch member, and the thermal conductivity of the nozzle touch member is the flow path. The sprue bush according to claim 1, wherein the sprue bush is smaller than a thermal conductivity of the main body member.   The material of the sprue body is carbon steel, the material of the flow path body member is titanium having a thermal conductivity smaller than that of carbon steel, and the material of the nozzle touch member is zirconia having a thermal conductivity smaller than that of titanium. The sprue bushing according to claim 4.

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