JP3255061U - Sprue bush and its nozzle touch member - Google Patents

Abstract

[Problem] To provide a sprue bush and its nozzle touch member for preventing stringing, which improves positioning and reproducibility of molding conditions.
[Solution] The solution provides a sprue bush comprising a sprue bush body 2 having an enlarged diameter portion 21 at one end of a cylindrical body 25 through which a sprue hole passes, a nozzle touch member 3 that can abut the center, and a fixing means 4 that connects the nozzle touch member and the sprue bush body and fixes them to the mold, wherein the resin introduction hole 32 has a cooling means for preventing stringing, the enlarged diameter portion of the sprue bush body is provided with a first engaging means, the nozzle touch member is provided with a second engaging means, the first engaging means and the second engaging means lock together to position the nozzle touch member so that the central axis of the resin introduction hole and the central axis of the sprue hole coincide, and rotation of the nozzle touch member in the circumferential direction is prevented.
[Selection Diagram] Figure 1

Description

This invention relates to a metal sprue bush used when introducing molten resin from the nozzle of an injection molding machine into a mold, and to its constituent components, including a nozzle touch portion that contacts the nozzle of the injection molding machine. More particularly, it relates to a sprue bush and its nozzle touch portion having a stringing prevention function.

Conventionally, a sprue bush with a stringing prevention function is known to have, for example, a recess formed on the nozzle-touch end face of a sprue bush body having a sprue hole, a nozzle-touch member fitted into the recess, and a nozzle-touch surface and a through-hole provided on the nozzle-touch member, with a partition wall provided in the through-hole for cooling purposes (see, for example, Patent Document 1). In the invention described in Patent Document 1, the nozzle-touch member can be replaced when it becomes worn out.

Furthermore, a cartridge-type sprue bush unit is known, which includes a cartridge with a sprue hole for preventing stringing, and in which the cartridge (nozzle touch member) is sandwiched between the sprue bush body and the cartridge holder (see, for example, Patent Document 2). In the invention described in Patent Document 2, the cartridge is also replaceable.

Furthermore, a sprue bush for preventing stringing is known, which has multiple ribs arranged radially for the purpose of cooling the molten resin (see, for example, Patent Document 3).
Figure 8 of Patent Document 3 shows a configuration in which a bushing component (nozzle touch member) is placed on the sprue bushing body, and a ring-shaped component is placed over it from above to clamp and fix the bushing component.

Japanese Patent Publication No. 2004-66563 Registered Utility Model No. 3153374 Publication Patent No. 6049927

As described above, it is well known that in sprue bushes with anti-stringing functionality, the nozzle touch member can be replaced. However, the invention described in Patent Document 1 involves fitting the nozzle touch member into a recess in the sprue bush body, or lightly crimping a portion of the periphery of the nozzle touch member with a punch or similar tool to secure it. This method has the drawback of easily resulting in inaccurate fixing of the nozzle touch member. If the central axis of the nozzle touch member is misaligned with the central axis of the recess or sprue hole in the sprue bush body, it can cause problems with the flow of molten resin, potentially leading to short shots or deterioration of the reproducibility of molding conditions.

Furthermore, in configurations such as those described in Patent Documents 2 and 3, where the nozzle touch member is covered by a cartridge holder or ring-shaped component and secured with two screws, it is generally assumed that the central axis of the nozzle touch member and the central axis of the sprue hole in the sprue bush body coincide. However, in both Patent Documents 2 and 3, the circumferential direction is not fixed in any way, and the circumferential position of the nozzle touch member changes each time it is cleaned or replaced. Therefore, if there is a cooling means such as a partition in the resin introduction hole, as in Patent Document 1, the position of the partition changes, and it cannot be said that sufficient reproducibility of molding conditions is ensured.

This invention was made in view of the above circumstances, and aims to provide a sprue bush and its nozzle touch member that can improve the coaxiality between the central axis of the nozzle touch member and the central axis of the sprue hole, and improve the reproducibility of molding conditions.

A sprue bush comprising a sprue bush body having an enlarged diameter portion at one end of a cylindrical body through which a sprue hole passes, a nozzle touch member having a resin introduction hole connected to the sprue hole in its center and capable of contacting the enlarged diameter portion of the sprue bush body, and a fixing means for fixing the nozzle touch member and the sprue bush body by connecting the nozzle touch member and the sprue bush body and fixing them to a mold, wherein the resin introduction hole has a cooling means for preventing stringing, wherein the enlarged diameter portion of the sprue bush body is provided with a first engaging means, and the nozzle touch member is provided with a second engaging means, and the first and second engaging means are locked together so that the central axis of the resin introduction hole and the central axis of the sprue hole coincide, and the rotation of the nozzle touch member in the circumferential direction is prevented, is provided as a means to solve the above problem.

According to the present invention, a sprue bush comprises a sprue bush body having an enlarged diameter portion at one end of a cylindrical body through which a sprue hole passes, a nozzle touch member having a resin introduction hole in the center connected to the sprue hole and capable of contacting the enlarged diameter portion of the sprue bush body, and a fixing means for fixing the nozzle touch member and the sprue bush body by connecting the nozzle touch member and the sprue bush body and fixing them to a mold, wherein the resin introduction hole has a cooling means for preventing stringing, and the enlarged diameter portion of the sprue bush body is provided with a first engaging means, and the nozzle The nozzle touch member is equipped with a second engaging means, and by engaging the first and second engaging means, it is positioned so that the central axis of the resin introduction hole and the central axis of the sprue hole coincide, and rotation of the nozzle touch member in the circumferential direction is prevented. Therefore, the positioning by the first and second engaging means ensures that the cooling means of the resin introduction hole is always positioned in the same location, and circumferential displacement is prevented, thereby improving the reproducibility of molding conditions and enhancing the coaxiality between the sprue bush body and the nozzle touch member.

This is a perspective view showing a sprue bush according to an embodiment of the present invention. This is a perspective view showing the state of a sprue bush according to an embodiment of the present invention before assembly. (a) A plan view, (b) A cross-sectional view along A-A, and (c) A cross-sectional view along B-B show the nozzle touch member of a sprue bush according to an embodiment of the present invention. This is a perspective view showing a nozzle touch member used in a spray bush according to another embodiment of the present invention, (a) a perspective view showing a resin introduction hole divided into two by a partition wall, (b) a perspective view showing a resin introduction hole divided into four by a partition wall, and (c) a shape in which a notch is formed along the nozzle contact portion.

A sprue bush according to one embodiment of the present invention comprises a sprue bush body having an enlarged diameter portion at one end of a cylindrical body through which a sprue hole passes; a nozzle touch member having a resin introduction hole connected to the sprue hole in its center and capable of contacting the enlarged diameter portion of the sprue bush body; and a fixing means for fixing the nozzle touch member and the sprue bush body by connecting the nozzle touch member and the sprue bush body and fixing them to a mold, wherein the resin introduction hole has a cooling means for preventing stringing. In this sprue bush, the enlarged diameter portion of the sprue bush body is provided with a first engaging means, and the nozzle touch member is provided with a second engaging means. By engaging the first and second engaging means, the sprue bush can be positioned so that the central axis of the resin introduction hole and the central axis of the sprue hole coincide, and rotation of the nozzle touch member in the circumferential direction is prevented (first configuration).

According to the first configuration described above, the cooling means for the resin introduction hole is always positioned in the same location by the positioning provided by the first and second engaging means, and circumferential displacement is prevented. This improves the reproducibility of molding conditions and enhances the coaxiality between the sprue bush body and the nozzle touch member.

In another embodiment of the present invention, the sprue bush has the first configuration described above, but the first engaging means is a protrusion projecting from the enlarged diameter portion of the sprue bush body toward one end, and the second engaging means can be a notch cut out from the side of the nozzle touch member (second configuration).

According to the second configuration described above, in addition to achieving the effects of the first configuration, the protrusion and the notch are locked together on the same plane, thus reducing bulk and adding space-saving benefits.

A sprue bush according to another embodiment has the second configuration described above, but the protrusions are positioned at the front and rear, the notches are formed to include the front left and right and rear left and right of the nozzle touch member, and the nozzle touch member has corners with first and second surfaces at the front left and right and rear left and right positions, with the first and second surfaces of the corners contacting and locking with the protrusions (third configuration).

According to the third configuration described above, the protrusions are positioned at the front and rear, the notches are formed including the front left and right and rear left and right of the nozzle touch member, and the notches have corners with first and second surfaces at the front left and right and rear left and right positions of the nozzle touch member. Since the first and second surfaces of the protrusions engage with the protrusions, displacement of the nozzle touch member relative to the sprue bush body in the front, rear and left and right directions is prevented, and the reliability of the effects of the first configuration described above can be increased.

Furthermore, a sprue bush according to another embodiment may have the third configuration described above, wherein the protrusion of the sprue bush body has a first surface that abuts against the first surface of the corner of the nozzle touch member and a second surface that abuts against the second surface of the corner, and a relief portion is provided at the intersection of the first and second surfaces that constitute the corner (fourth configuration).

According to the fourth configuration described above, by providing a relief portion at the intersection of the first and second surfaces constituting the corner, it is possible to prevent the occurrence of a rounded surface during processing and to ensure secure engagement with the protrusion.

Furthermore, the nozzle touch member used in any of the first to fourth configurations is an essential component for forming the sprue bush of the first to fourth configurations, improving the reproducibility of molding conditions and enhancing coaxiality with the sprue bush body. Additionally, it is possible to manufacture the nozzle touch member as a standalone consumable part.

The following describes a sprue bush and its nozzle touch member according to an embodiment of the present invention. In the figures, the same or corresponding parts are denoted by the same reference numerals, and their descriptions are not repeated. For clarity of explanation, the drawings referenced below may show simplified or schematic representations of the components, or some components may be omitted. Furthermore, the dimensional ratios between components shown in each figure do not necessarily represent actual dimensional ratios.

In describing the embodiments of this invention, the "one end" of the sprue bush 1 refers to the side that the injection molding nozzle contacts, and the "other end" refers to the mold side on the opposite side.

As shown in Figures 1 and 2, the sprue bush 1 according to this embodiment of the present invention comprises a sprue bush body 2, a nozzle touch member 3, and two fixing screws 4, 4.

As shown in Figure 2, the sprue bush body 2 has an enlarged diameter portion 21 at one end of a cylindrical body 25 through which the sprue hole 20 passes. The sprue hole 20 slightly enlarges in diameter from one end to the other.

The enlarged diameter portion 21 of the sprue bush body 2 is formed in a cylindrical or disc shape with a height less than its width, and has a protrusion 23 projecting from its end face 22 toward one end. In this embodiment, two protrusions 23 are provided opposite each other in a plan view. In other words, the protrusions 23 are provided at 180° intervals with respect to the center of the circle constituting the enlarged diameter portion 21 in a plan view.

Furthermore, two through-holes 24 on the end face 22 are provided, facing each other in a plan view. In other words, the through-holes 24 on the main body are provided at 180° intervals from the center of the circle constituting the enlarged diameter portion 21 in a plan view, and at positions offset by 90° from the position of the protrusion. The through-holes 24 on the main body are used for attaching the sprue bush to the mold, and also for positioning and fixing the sprue bush body 2 and the nozzle touch member 3.

The protrusion 23 has a generally semi-circular contour in plan view and has an upper surface 230 and four side surfaces. The four side surfaces are a side circumferential surface 231 that shares a contour with the enlarged diameter portion, a first side surface 232 located opposite the side circumferential surface 231, and two second side surfaces 233, 233 extending from both ends of the first side surface 232 to both ends of the side circumferential surface 231. The first side surface 232 and the second side surfaces 233 are perpendicular in plan view, and the corners 234 formed by the first side surfaces 232 and the second side surfaces 233 serve as the engagement points with the nozzle touch member 3 on the protrusion 23. In this embodiment, there are a total of four corners 234, consisting of the two protrusions 23. As described above, since the two protrusions are positioned opposite each other, each corner 234 is arranged such that the line connecting the vertices of adjacent corners 234 forms a rectangle in plan view.

As shown in Figures 1 to 3, the nozzle touch member 3 has a shape with a notch 30A at the front and a notch 30B at the rear of a disc. At the upper center, there is a nozzle contact portion 31 that curves and drops inward towards the center, and a resin introduction hole 32 opening at the bottom of its center. On the left and right sides of the disc, there are screw mounting portions 34 with a counterbore shape.

In this embodiment, a partition wall 33 is provided within the resin introduction hole 32, dividing the space of the introduction hole into three sections. The partition wall 33 is a cooling means that cools the molten resin to prevent stringing. The central axis of the resin introduction hole 32 coincides with the center of the sprue hole 20 of the sprue bush body 2 when engaged with the sprue bush body 2.

The front notch 30A of the nozzle touch member 3 has a first restricting surface 300A that is continuous in the left-right width direction and two second restricting surfaces 301A that are formed in the front-rear direction. Similarly, the rear notch 30B of the nozzle touch member 3 has a first restricting surface 300B that is continuous in the left-right width direction and two second restricting surfaces 301B that are formed in the front-rear direction.
The corner portion 35A is formed by the first surface 300A and the second surface 301A of the nozzle touch member 3. Similarly, the corner portion 35B is formed by the first surface 300B and the second surface 301B of the nozzle touch member 3. Furthermore, relief portions 302 are provided at each intersection of the first surfaces 300A, 300B and the second surfaces 301A, 301B to ensure good engagement with the sprue bush body. More specifically, due to the manufacturing process, rounded surfaces (R-surfaces) tend to form at each intersection of the first surfaces 300A, 300B and the second surfaces 301A, 301B. These rounded surfaces hinder engagement with the sprue bush body. By forming the relief portions 302 to prevent the formation of rounded surfaces, secure engagement with the sprue bush body is ensured.

The screw mounting portion 34 of the nozzle touch member 3 has a through hole 340. The central axis of the through hole 340 coincides with the central axis of the through hole 24 on the body side of the sprue bush body 2 when engaged with the sprue bush body 2.

The fixing screw, which serves as the fastening means, has a head on the base end and a screw groove on the tip end. The head is larger than the through-hole 340 of the nozzle touch member 3, but smaller than its counterbore diameter.

Although not shown in the illustration, the mold has a sprue bush mounting hole for attaching the sprue bush, and two screw holes around the sprue bush mounting hole for screwing in fixing screws 4, 4. These are known configurations for attaching conventional spray bushes, and the sprue bush of this invention can use conventional molds as is.

The sprue bush body 2, nozzle touch member 3, and fixing screw 4, having the above configuration, can be fixed to the mold using the following procedure.

With the nozzle touch member 3 facing forward relative to the front protrusion of the sprue bush body 2, the nozzle touch member 3 is placed on the sprue bush body 2 such that the central axes of the sprue hole 20 and the through hole 24 of the sprue bush body 2 align with the central axes of the resin introduction hole 32 and the through hole 340 of the nozzle touch member 3. The nozzle touch member 3 fits between the front and rear protrusions 23, 23 of the sprue bush body 2. In this state, the first side surface 232 and the second side surface 233 of the front protrusion 23 of the sprue bush body 2 come into contact with the first restricting surface 300A and the second restricting surface 301A of the nozzle touch member 3, and the first side surface 232 and the second side surface 233 of the rear protrusion 23 of the sprue bush body 2 come into contact with the first restricting surface 300B and the second restricting surface 301B of the nozzle touch member 3.

In this state, the four corners 234 formed by the first side surface 232 and the second side surface 233 of the sprue bush body 2 engage with the corners 35A and 35B. Therefore, the engagement of these corners 234 with the corners 35A and 35B causes the central axis of the sprue hole 20 to coincide with the central axis of the resin introduction hole 32, and the central axis of the through hole 24 on the body side to coincide with the central axis of the through hole 340 of the nozzle touch member 3. Furthermore, the direction of each wall 33 is always determined to be the same direction. Moreover, since the engagement of the four corners 234 with the corners 35A and 35B prevents circumferential displacement, sufficient reproducibility of molding conditions can be ensured.

The cylindrical body 25 of the sprue bush body 2 is inserted into the sprue bush mounting hole of the mold (not shown in the illustration), and the fixing screw 4 is screwed into the screw hole of the mold, connecting the through hole 340 of the nozzle touch member 3 and the through hole 24 on the body side of the sprue bush body 2.

Alternatively, the sprue bush body 2 may be inserted first into the sprue bush mounting hole of the mold, and then the nozzle touch member 3 and the sprue bush body 2 may be engaged.

As described above, the spray bush 1 according to the embodiment of the present invention allows for extremely simple operation to enhance the coaxiality between the sprue bush body 2 and the nozzle touch member 3, thereby ensuring sufficient reproducibility of molding conditions.

Furthermore, in the above embodiment, the partition wall 33 provided as a cooling means to prevent stringing in the resin introduction hole 32 of the nozzle touch member 3 is configured such that three partition walls 33 are joined at the center of the resin introduction hole 32, dividing the space within the resin introduction hole 32 into three sections. However, the present invention is not limited to this configuration. For example, as shown in Figure 4(a), the space within the resin introduction hole 32 may be divided into two sections, or as shown in Figure 4(b), it may be divided into four sections. The number of partition walls 33 can be selected based on a balance between the ease of passage of the fluid resin and the cooling efficiency for preventing stringing.

Furthermore, in the above embodiment, the nozzle touch member 3 has a configuration in which the first surfaces 300A and 300B extend across the entire width direction due to the notches 30A and 30B. However, the present invention is not limited to this configuration. For example, as shown in Figure 4(c), the first surfaces 300A and 300B can be formed only at both ends in the width direction, and together with the second surfaces 301A and 301B, they can have corner portions 35A and 35B.

Furthermore, when using the nozzle touch member 3 shown in Figures 4(a) and 4(b), the orientation of the partition wall 33 remains unchanged even when rotated 180° in plan view. Therefore, it offers the advantage of being able to perform the installation work without having to check the front or back of the nozzle touch member 3.

In contrast, when using the nozzle touch member 3 shown in the above embodiment, the orientation of the partition wall 33 changes when rotated 180° in plan view. Therefore, it becomes necessary to check the front and rear. However, by providing identification markings to distinguish between the front and rear, for example, the burden of checking can be reduced.

In this invention, the nozzle touch member 3 can be detached or replaced when cleaning becomes necessary or when it becomes worn out. This not only achieves the effects of the invention described above, but also offers excellent cost-effectiveness.

B Rear D Downward F Front L Left R Right U Upward 1 Sprue bush 2 Sprue bush body 20 Sprue hole 21 Enlarged diameter portion 22 End face 23 Protrusion 230 Top surface 231 Side surface 232 First side surface 233 Second side surface 234 Corner portion 24 Through hole on body side 25 Cylindrical body 3 Nozzle touch member 30A Notch 30B Notch 300A First surface 300B First surface 301A Second surface 301B Second surface 302 Relief portion 31 Nozzle contact portion 32 Resin introduction hole 33 Partition wall 34 Screw mounting portion 340 Through hole 35A Corner portion 35B Corner portion 4 Fixing screw (fastening means)

Claims (5)

A sprue bush comprising: a sprue bush body having an enlarged diameter portion at one end of a cylindrical body through which a sprue hole passes; a nozzle touch member having a resin introduction hole in the center connected to the sprue hole and capable of contacting the enlarged diameter portion of the sprue bush body; and a fixing means for fixing the nozzle touch member and the sprue bush body by connecting the nozzle touch member and the sprue bush body and fixing them to a mold, wherein the resin introduction hole has a cooling means for preventing stringing,
The enlarged diameter portion of the sprue bush body is provided with a first engagement means,
The nozzle touch member is equipped with a second engagement means,
A sprue bush in which the first engaging means and the second engaging means are locked together so that the central axis of the resin introduction hole and the central axis of the sprue hole coincide, and rotation of the nozzle touch member in the circumferential direction is prevented. The sprue bush according to claim 1, wherein the first engaging means is a protrusion projecting from the enlarged diameter portion of the sprue bush body toward one end, and the second engaging means is a notch formed by cutting out the side surface of the nozzle touch member. The sprue bush according to claim 2, wherein the protrusions are positioned forward and backward, the notches are formed including the front left and right and rear left and right of the nozzle touch member, and the sprue bush has corners with a first surface and a second surface at the front left and right and rear left and right positions of the nozzle touch member, and the first and second surfaces of the corners abut and lock with the protrusions. The protrusion of the sprue bush body has a first side surface that contacts the first surface of the corner of the nozzle touch member, and a second side surface that contacts the second surface of the corner.
The sprue bush according to claim 3, wherein a relief portion is provided at the intersection of the first surface and the second surface constituting the corner. A nozzle touch member constituting a sprue bush according to any one of claims 1 to 4.