JP4853626B2 - Hot runner sprue - Google Patents

Description

  The present invention relates to a hot runner sprue.

  In the thermoplastic resin injection mold 10 illustrated in FIG. 14, the hot runner can heat the manifold 12 and the nozzle 13, keep the resin 14 in a molten state, and cool and remove only the product portion 16. It is a thing. The injection mold 10 is provided with a hot runner block 18 that secures a flow path of the resin 14 at the time of injection. In addition, the part shown with the code | symbol 20 in FIG. 14 is a heater. (For example, Patent Document 1)

JP-A-4-67923 (first page, second page, FIG. 1, FIG. 2)

By the way, as shown in FIG. 15, the general valve gate type hot runner block 22 generally has a structure for controlling the supply of resin to the mold product part by closing the gate 24 of the nozzle 13 with a stem 26. It is. However, in this structure, when the molding machine nozzle is separated from the nozzle touch part 28a of the hot runner sprue 28 due to setup change or the like, the resin in the manifold 12 and the hot runner sprue 28 flows backward and leaks from the nozzle touch part 28a. The internal pressure of the manifold 12 and the hot runner sprue 28 is reduced to atmospheric pressure. Then, air enters the hot runner sprue 28 and the manifold 12 from the nozzle touch portion 28a, and bubbles 32 are generated in the runner 30. During the next molding, these bubbles are formed into silver strips (one of molding defects). ). Since the silver strip of the molded product is generated until all of the resin in the nozzle 13, the manifold 12 and the hot runner sprue 28 is injected from the gate 24 and replaced with resin without air bubbles, the production amount per lot is small. In the case of molded products, a problem has been pointed out that the defect rate increases.
The present invention has been made in view of the above problems, and the object of the present invention is to prevent resin leakage when the molding machine nozzle is separated from the hot runner sprue and to prevent bubbles from being mixed into the runner, thereby forming the molding. It is to avoid the occurrence of silver stripes in the product.

In order to solve the above problems, a hot runner sprue according to the present invention is a hot runner constituting a connecting portion with a molding machine nozzle for feeding the resin supplied from the molding machine nozzle to the manifold of the hot runner block. A sprue,
The main body of the hot runner sprue is formed with a nozzle touch surface with the nozzle of the molding machine and a resin supply path that opens to the nozzle touch surface and communicates with the manifold. A seal that blocks the opening from the inside of the resin supply path without disturbing the resin flow at the time of resin supply and receiving the back flow pressure of the resin in the resin supply path when the resin supply from the molding machine nozzle is stopped A member is provided, and the resin supply path is formed with a stepped portion having a diameter that discontinuously increases from the opening to the manifold. The seal member has a step of the resin supply path. A main seal portion having a close contact surface that contacts the shoulder of the step portion from the manifold side toward the opening side, and a portion protruding from the main seal portion and extending from the step portion of the resin supply path to the opening And a sub-seal portion having a fitting surface that fits without a gap, and the main seal portion of the seal member from the molding machine nozzle while ensuring the resin flow when the resin is supplied from the molding machine nozzle. A pressure receiving portion that receives the back flow pressure of the resin in the resin supply path when the resin supply is stopped is provided, and the sub seal portion has an opening from the inside of the resin supply path without causing a step difference from the nozzle touch surface. It is configured to be closed, or its protruding height is formed lower than the portion from the step portion of the resin supply path to the nozzle touch surface, and is held in the main seal portion so as to be able to protrude and retract with respect to the main seal portion. And
Further, the main seal portion is provided with a reverse flow pressure of the resin in the resin supply passage when the supply of resin from the molding machine nozzle is stopped to cause the sub seal portion to protrude from the main seal portion. The resin flow dividing means is provided .

According to the present invention, when the molding machine nozzle is separated from the nozzle touch surface of the hot runner sprue and the external pressurization to the resin in the resin supply passage of the hot runner sprue stops, the inside of the resin supply passage that surpasses the atmospheric pressure The seal member receives the reverse flow pressure of the resin, and the seal member closes the opening of the resin supply path from the inside of the resin supply path. Therefore, resin leakage from the hot runner sprue is eliminated, and bubbles can be prevented from being mixed into the runner.
When the resin is supplied from the molding machine nozzle, the seal member receives the pressure of the resin supplied from the molding machine nozzle and moves backward from the opening of the resin supply path into the resin supply path, thereby removing the resin from the hot runner sprue. It becomes possible to guide to the resin supply path. At this time, since the seal member is provided so as not to hinder the resin flow when the resin is supplied from the molding machine nozzle, the resin is smoothly filled into the product portion of the mold.

  Further, the main seal portion of the seal member receives the back flow pressure of the resin in the resin supply passage and abuts against the shoulder of the step portion of the resin supply passage from the manifold side to the opening side, so that the molding machine nozzle The nozzle touch is not obstructed, and the opening is closed from the inside of the resin supply path. In addition, the sub seal part protruding from the main seal part fits into the part from the step part of the resin supply path to the opening without any gap, so that the opening of the resin supply path is closed without causing a step with the nozzle touch surface. It will come off.

  Further, in the present invention, the main seal portion of the seal member secures the resin flow when the resin is supplied from the molding machine nozzle, and the resin in the resin supply path when the resin supply from the molding machine nozzle is stopped. By providing a pressure receiving part that receives the reverse flow pressure, the main seal part can abut against the shoulder of the step part of the resin supply path from the manifold side to the opening side, thereby preventing resin leakage. Become. Further, since the resin flow at the time of supplying the resin from the molding machine nozzle is not hindered, the injection molding is performed smoothly.

  Further, in the present invention, when the sub seal portion is configured to close the opening without generating a step from the nozzle touch surface from the inside of the resin supply path, the opening of the resin supply path is: Since the sub seal part closes the nozzle touch surface without causing a step, when the molding machine nozzle once separated comes into contact with the nozzle touch surface of the hot runner sprue again, the gap between the molding machine nozzle and the nozzle touch surface Air does not intervene. Therefore, the air bubbles are not mixed into the runner from between the molding machine nozzle and the nozzle touch surface.

  Further, when the protrusion height of the sub seal portion is formed lower than the portion from the step portion of the resin supply path to the nozzle touch surface, it is between the nozzle touch surface and the sub seal portion. Since the minute gap is generated, the sub seal portion does not block the opening from the inside of the opening without causing a step difference from the nozzle touch surface. However, even if air having such a small gap is mixed into the resin, no silver strip is generated in the product.

Further, in the present invention, the sub seal portion of the seal member is held by the main seal portion so as to be able to protrude and retract with respect to the main seal portion, and the main seal portion is not supplied with resin from the molding machine nozzle. Since the resin flow distribution means is provided for applying the back flow pressure of the resin in the resin supply path to the sub seal portion and projecting the sub seal portion from the main seal portion, the main seal portion is molded. When the resin supply from the machine nozzle is stopped, the sub-seal part receives the back flow pressure of the resin in the resin supply path and comes into contact with the shoulder of the step of the resin supply path from the manifold side to the opening side. Also, it receives the back flow pressure of the resin through the resin diverting means. Then, the sub seal part protruding from the main seal part fits into the part from the step part of the resin supply path to the opening without any gap, so that the opening of the resin supply path is closed without causing a step with the nozzle touch surface. It will come off. On the other hand, when the resin is supplied from the molding machine nozzle, the sub seal part receives the resin supply pressure from the molding machine nozzle and is immersed in the main seal part, and the main seal is also separated from the shoulder of the step part of the resin supply path. By retreating from the opening of the resin supply path into the resin supply path, the resin flow to the resin resin supply path is ensured.

Further, in the present invention, a plurality of guide protrusions extending in the resin flow direction are formed on the inner wall of the resin supply path, and the main seal portion of the seal member is slidably guided to the guide protrusions. It is desirable that the slide pin is configured.
  With this configuration, when the resin is supplied from the molding machine nozzle, the resin flows in a space formed between the guide protrusion and the slide pin that is slidably guided to the resin, and the resin flow in the resin supply path is ensured. In addition, the main seal portion is slidably guided by the guide protrusion, so that it receives the back flow pressure of the resin in the resin supply passage when the resin supply from the molding machine nozzle is stopped, and the shoulder of the step portion of the resin supply passage On the other hand, it is possible to contact from the manifold side toward the opening side. In addition, when the resin is supplied from the molding machine nozzle, the seal member receives the pressure of the resin supplied from the molding machine nozzle, and moves backward from the opening of the resin supply path into the resin supply path, thereby removing the resin from the hot runner sprue. It is possible to smoothly lead to the resin supply path.

Here, the sub seal portion is configured such that a part of a sub slide pin that is slidably guided to a cylinder chamber formed in the main seal portion can protrude and retract from a tip portion of the main seal portion. The main seal portion may be provided with a communication hole that communicates the cylinder chamber and the resin supply path as the resin flow dividing means.
According to this configuration, the main seal portion receives the back flow pressure of the resin in the resin supply passage when the resin supply from the molding machine nozzle is stopped, and opens from the manifold side to the shoulder of the step portion of the resin supply passage. When abutting toward the side, the sub slide pin that is slidably guided in the cylinder chamber also receives the backflow pressure of the resin flowing into the cylinder chamber through the communication hole. Then, a part of the sub slide pin protrudes from the main seal portion and fits into a portion extending from the step portion of the resin supply path to the opening, so that the opening of the resin supply path forms a step with the nozzle touch surface. It will be closed without any problems.

The main seal is rotatably supported about the axis by a guide protrusion formed on the inner wall of the resin supply path, and the guide protrusion is not affected by the rotation phase relative to the resin supply path. It is desirable that one or two or more communication holes are provided at a position where they are not blocked.
In the present invention, the main seal is not provided with a rotation stop for simplification of the structure, and the main seal portion is rotatably supported around the shaft by the guide protrusion formed on the inner wall of the resin supply path. In addition, since the one or more communication holes are provided at a position where the guide protrusion is not blocked regardless of the rotational phase of the main seal portion with respect to the resin supply path, the sub seal portion is provided. Receives the backflow pressure of the resin in the resin supply path when the resin supply from the molding machine nozzle is stopped through the communication hole, and protrudes from the main seal portion.

  In the present invention, it is desirable that the cylinder chamber is provided with a spring that biases the sub seal portion in a direction in which the sub seal portion protrudes from the main seal portion. With this configuration, the sub seal portion is pushed out of the main seal portion by the elastic force of the spring together with the back flow pressure of the resin supplied through the communication hole. Further, even when the internal pressure of the resin supply path is reduced due to resin shrinkage caused by cooling the hot runner, the protruding state of the sub seal portion from the main seal portion is maintained by the spring.

  Further, the pressure of the pressure receiving portion of the main seal portion is such that the back flow pressure of the resin received by the main seal portion exceeds the sum of the back flow pressure of the resin received by the sub seal portion and the elastic force of the spring in the cylinder chamber. If the pressure receiving area and the opening area of the communication hole are determined, the main seal portion is first subjected to the back flow pressure of the resin in the resin supply path when the resin supply from the molding machine nozzle is stopped. However, it comes into contact with the shoulder of the step portion of the resin supply path from the manifold side toward the opening side, so that resin leakage can be avoided. Subsequently, the sub seal part protrudes from the main seal part and fits into the opening extending from the step part of the resin supply path to the opening, so that the opening of the resin supply path forms a step with the nozzle touch surface. It will be closed without any problems.

  Since the present invention is configured as described above, it is possible to prevent resin leakage when the molding machine nozzle is separated from the hot runner sprue, and to prevent air bubbles from entering the runner, thereby avoiding the occurrence of silver strips in the molded product. It becomes possible.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Here, parts that are the same as or correspond to those in the prior art are denoted by the same reference numerals, and detailed description thereof is omitted.
As shown in FIGS. 1 to 3, the hot runner sprue 34 according to the embodiment of the present invention includes a main body base portion 38 that is in direct contact with the manifold 12, a main body intermediate portion 40 that overlaps the main body base portion 38, and a main body intermediate portion. It has a main body 44 having a cylindrical shape as a whole, which is composed of a main body tip portion 42 that overlaps the portion 40. The main body base portion 38, the main body intermediate portion 40, and the main body front end portion 42 are fixed to the manifold 12 by bolts 46. The main body base 38 and the main body intermediate portion 40 are accurately positioned with respect to the manifold 12 by positioning pins 48.

The main body base 38 includes a hemispherical recess 38 a at the center, and a communication hole 38 b communicating with the manifold 12 is formed at the center of the hemispherical recess 38 a.
Further, as shown in FIG. 5, a hole 40 a having a constant diameter is formed in the main body intermediate portion 40 so as to penetrate the center portion, and the hole 40 a has an axial direction (resin flow direction) of the main body intermediate portion 40. A plurality of guide protrusions 40b extending toward the surface are formed. In the illustrated example, four guide projections 40b are formed at equal intervals (90 ° intervals) in the circumferential direction. The diameter of the circle C1 connecting the tip ends of the guide protrusions 40b is given for sliding and guiding a slide pin 54 described later. On the other hand, the diameter of the hole 40a is a diameter for ensuring the resin flow when the resin is supplied from the molding machine nozzle 36, as will be described later.
In addition, a deep counterbore 40c having the same diameter as or slightly larger than the hole 40a is formed at one end of the hole 40a (the end on the side in contact with the main body tip 42). By providing the counterbore 40c, a space for moving the cap 60, which will be described later, is secured, and one end of the guide projection 40b (the end facing the main body tip 42) is a stopper for the cap 60, which will be described later. It will function as the surface 40d. And resin flow part PA (FIG. 2, FIG. 8) is formed between the hole 40a, each guide protrusion 40b, and the slide pin 54 mentioned later. Note that reference numeral 40 e in FIG. 5 is an insertion hole for the bolt 46.

  Further, a nozzle touch surface 42a that is recessed in a spherical shape following the spherical molding machine nozzle 36 is formed on the main body tip portion 42, and a sub-slide pin 52 (to be described later) is formed at the center of the nozzle touch surface 42a. There is an opening 42b (see FIG. 9) for fitting (however, a gap is secured so that the sub slide pin 52 can slide). Further, the diameter of the opening 42b is discontinuously increased in a state where a necessary thickness is ensured in a portion where the nozzle touch surface 42a is formed, thereby forming a stepped portion 42c (see FIG. 9). The The diameter of the enlarged diameter portion 42d (see FIG. 9) formed at the step 42c of the opening 42b is the same as the diameter of the counterbore 40c of the intermediate body portion 40. Further, the diameter of the enlarged diameter portion 42d (and the counterbore 40c) is a diameter with which a rib 60e of the cap 60 described later is in sliding contact (see FIGS. 8 and 9).

The main body 44 formed by superimposing these parts includes an opening 42b and a diameter-expanded portion 42c of the main body tip portion 42, a deep counterbore 40c and a hole 40a of the main body intermediate portion 40, and a hemispherical shape of the main body base portion 38. The resin supply path 50 is formed by the recess 38a and the communication hole 38b.
In the resin supply path 50 formed in the main body 44, a slide pin 54 configured so that the sub slide pin 52 can be projected and retracted from the tip is slidable in the axial direction of the slide pin 54 by the guide protrusion 40b. It is supported by. Note that the slide pin 54 is rotatably supported by the guide protrusion 40 b about the axis of the slide pin 54, and is not particularly stopped in the resin supply path 50.

As shown in FIG. 6, the slide pin 54 is a rod-shaped member having a base end portion 54 a that is pointed in a conical shape, and a tip end side thereof is cylindrical, and a cylinder chamber 54 b is formed. The inner wall of the cylinder chamber 54b is provided with a diameter capable of slidingly guiding the large-diameter base portion 52a (FIG. 8) of the sub-slide pin 52, and the sub-slide pin 52 is provided on the bottom surface of the cylinder chamber 54b. A screw hole 54c for fixing a stopper pin 56 (FIG. 8) that limits the movable range is formed. The slide pin 54 is formed with a communication hole 54 d that connects the inner wall of the cylinder chamber 54 b and the outer wall of the slide pin 54. In the illustrated example, three communication holes 54d are provided at equal intervals (120 ° intervals) in the circumferential direction of the circular stopper pin wall surface. As will be described later, the communication hole 54d applies, to the large-diameter base portion 52a of the sub-slide pin 52 in the cylinder chamber 54d, the reverse flow pressure of the resin in the resin supply path 50 when the resin supply from the molding machine nozzle 36 is stopped. Thus, the sub slide pin 52 is projected from an opening 60a of the cap 60 described later. Therefore, in the embodiment of the present invention, the communication hole 54d constitutes “resin distribution means”.
Furthermore, a screw 54e for screwing with a cap 60 described later is formed at the upper end of the outer peripheral wall of the slide pin 54. In FIG. 6, the portion indicated by reference numeral 54f is a so-called two-sided width for pointing in the tool.

  Further, as shown in FIGS. 8 and 9, a coil spring 58 is inserted into the cylinder chamber 54b of the slide pin 54 so as to surround the stopper pin 56, and the sub slide pin 52 is inserted into the cylinder chamber 54b. The large-diameter base 52a is supported by the spring 58. In order to prevent the sub slide pin 52 from dropping from the cylinder chamber 54 b of the slide pin 54, a cap 60 is screwed into the screw 54 e of the slide pin 54.

  As shown in FIG. 7, the cap 60 has an opening 60 a through which the small diameter portion 52 b (FIG. 8) of the sub slide pin 52 is inserted on the distal end side, and a screw of the slide pin 54 on the proximal end side. A screw hole 60b having a diameter larger than that of the opening 60a is formed to be screwed into 54e. The opening 60 a has a diameter for slidingly guiding the small diameter portion 52 b of the sub slide pin 52. Further, the large-diameter base portion 52a of the sub slide pin 52 abuts on the step portion 60c between the opening 60a and the screw hole 60b, thereby restricting the protrusion of the sub slide pin 52 from the upper surface 60d of the cap 60 of the sub slide pin 52. Therefore, the large-diameter base portion 52a (FIG. 9) of the sub slide pin 52 cannot pass through the opening 60a. Further, around the cap 60, four ribs 60e are formed at equal intervals in the circumferential direction. The rib 60e constitutes a pressure receiving portion Pr (see FIG. 8) that receives the backflow pressure of the resin in the resin supply path 50. The base end surface 60g of the cap 60 also constitutes a pressure receiving portion Pr (see FIG. 8) that receives the back flow pressure of the resin in the resin supply path 50.

Further, the diameter of the circle C2 connecting the tip portions of the ribs 60e has a diameter that allows sliding contact with the enlarged diameter portion 42c of the main body tip portion 42 and the deep spot facing 40c of the main body intermediate portion 40. And in the state which the rib 60e of the cap 60 was slidably contacted with the diameter expansion part 42c of the front-end | tip part 42 of the main body, or the deep counterbore 40c of the main body intermediate part 40, between each rib 60e, resin flow part PA (FIG. 2, FIG. 8) is formed.
In addition, the part shown with the code | symbol 60f in FIG. 7 is a 2 surface width for pointing in a tool.

As described above, the sub-slide pin 52 has the large-diameter base 52a slidably guided by the inner wall of the cylinder chamber 54b of the slide pin 54, and when the resin supply from the molding machine nozzle 36 is stopped in the cylinder chamber 54d. The small diameter portion 52 b protrudes from the opening 60 a of the cap 60 by receiving the back flow pressure of the resin in the resin supply path 50. Further, the tip of the small diameter portion 52 b of the sub slide pin 52 is a spherical concave surface 52 c that is recessed in a spherical shape following the spherical molding machine nozzle 36. Therefore, as shown in FIG. 8, the nozzle touch surface 42a and the spherical concave surface 52c are stepped in a state in which the sub slide pin 52 is fitted in the opening 42b formed in the nozzle touch surface 42a of the main body tip portion 42 of the main body 44. It forms a close contact surface that is continuous without causing any problems and is in close contact with the spherical molding machine nozzle 36 without a gap.
In addition, in FIG. 1, the member shown with the code | symbol 62 is a band heater, and the part shown with the code | symbol 64 is a thermocouple hole.

As described above, the sub-slide pin 52, the slide pin 54, the cap 60, and the like do not disturb the resin flow when the resin is supplied from the molding machine nozzle 36, and the resin when the resin supply from the molding machine nozzle 36 is stopped. A seal member 66 is configured to receive the back flow pressure of the resin in the supply path and close the opening 42b from the inside of the resin supply path 50 without causing a step difference from the nozzle touch surface 42a.
Further, as shown in FIG. 8, the front end surface 60d (FIG. 7) of the cap 60 is in close contact with the shoulder 42e of the step formed on the main body front end portion 42, thereby preventing fluid leakage from the opening 42b. Therefore, a seal Sm (metal seal) is formed. Accordingly, in the embodiment of the present invention, the slide pin 54 constitutes a “main seal portion” of the seal member 66 together with the cap 60.
On the other hand, a part (small diameter portion) 52b of the sub slide pin 52 that is slidably guided in the cylinder chamber 54b formed in the slide pin 54 protrudes from the opening 60a of the cap 60 positioned at the tip of the main seal portion, and the main body. A seal Ss (metal seal) for preventing leakage of fluid from the opening 42b and eliminating air in the opening 42b by being fitted in the opening 42b formed in the tip portion 42 without any gap. It is. Therefore, in the embodiment of the present invention, the sub slide pin 52 constitutes a “sub seal portion” of the seal member 66.

Subsequently, the operation of the hot runner sprue 34 according to the embodiment of the present invention will be described with reference to FIGS.
First, in a state where the molding machine nozzle 36 is separated from the nozzle touch surface 42a of the hot runner sprue 34 by setup change or the like, as shown in FIG. 1 and FIG. 60 acts on the rib 60e and the base end face 60g (pressure receiving portion Pr: see FIG. 8). Then, the cap 60 and the slide pin 54 move in the resin supply path 50 and approach the opening 42b, and the step surface 60d of the cap 60 is formed in the main body front end portion 42 as shown in FIG. The seal Sm is formed in close contact with the shoulder 42e. Therefore, fluid leakage from the opening 42b is prevented.
Further, the backflow pressure of the resin in the resin supply path 50 is also applied to the large-diameter base 52a of the sub slide pin 52 in the cylinder chamber 54b through the communication hole 54d. Therefore, the large-diameter base portion 52a of the sub slide pin 52 is separated from the stopper pin 56 protruding from the bottom surface of the cylinder chamber 54b and comes into contact with the step portion 60c of the cap 60, and the small diameter portion 52b of the sub slide pin 52 is Project from the opening 60a. A seal Ss that prevents leakage of fluid from the opening 42b and eliminates air in the opening 42b is configured by fitting in the opening 42b formed in the front end portion 42 without any gap.

  As described above, the nozzle touch surface 42a of the hot runner sprue 34 and the spherical concave surface 52c of the sub slide pin 52 form a continuous spherical surface without causing a step. Therefore, when the molding machine nozzle 36 is in close contact with the nozzle touch surface 42a of the hot runner sprue 34, the nozzle touch surface 42a and the spherical concave surface 52c and the molding machine nozzle 36 are in close contact with each other without any gap. No air enters the hot runner sprue 34 from the opening 42b when the supply of air is started.

  When resin is supplied from the molding machine nozzle 36 that is in close contact with the nozzle touch surface 42 a of the hot runner sprue 34, the supply pressure of the resin acts on the spherical concave surface 52 c of the sub slide pin 52. Since the supply pressure of the resin from the molding machine nozzle 36 exceeds the resultant force of the back flow pressure of the resin in the cylinder chamber 54b and the elastic force of the coil spring 58, the sub slide pin 52 contracts the coil spring 58 and the cylinder chamber. The resin in 54b approaches the stopper pin 56 while being discharged from the communication hole 54d. Then, when the large-diameter base 52a comes into contact with the stopper pin 56, the movement of the large-diameter base 52a of the sub slide pin 52 in the cylinder chamber 54b is stopped. FIG. 1B shows a stroke S2 until the large-diameter base portion 52a of the sub slide pin 52 is separated from the step portion 60c of the cap 60 and contacts the stopper pin 56 of the cylinder chamber 54b. The small-diameter portion 52b of the sub slide pin 52 is formed to have a length that completely immerses in the opening 60a of the cap 60 (that is, the maximum protrusion amount of the sub slide pin 52 from the tip surface 60d of the cap 60). Is also S2.).

  Even after the small diameter portion 52 b of the sub slide pin 52 is immersed in the opening 60 a of the cap 60, the resin supply pressure from the molding machine nozzle 36 continues to act on the spherical concave surface 52 c of the sub slide pin 52. Accordingly, the resin supply pressure is transmitted from the sub slide pin 52 to the slide pin 54 via the stopper pin 56. At this time, the supply pressure of the resin from the molding machine nozzle 36 also acts on the rib 60e of the cap 60. Since the resin supply pressure from the molding machine nozzle 36 exceeds the backflow pressure of the resin in the resin supply path 50 of the slide pin 54, the front end surface 60 d of the cap 60 is a stepped portion of the main body front end 42 constituting the main body 44. The cap 60 and the slide pin 54 are also pushed into the interior of the resin supply path 50 while the sub slide pin 52 is completely immersed in the opening 60 a of the cap 60. Then, when the base end portion 60g of the cap 60 contacts the stopper surface 40d of the main body intermediate portion 40, the slide pin 54 and the cap 60 are stopped. The stroke S1 of the cap 60 and the slide pin 54 at this time is shown in FIG.

  As described above, since the resin flow portion PA (FIGS. 2 and 9) is formed between the ribs 60e of the cap 60 and between the guide protrusions 40b of the main body intermediate portion 40, molding is performed. The resin supplied from the machine nozzle 36 flows in the resin supply path 50 as shown by an arrow F in FIGS. 4 and 9 and is further supplied to the manifold 12.

Next, when the supply of the resin from the molding machine nozzle 36 is stopped, the backflow pressure of the resin in the resin supply path acts again on the rib 60e and the base end surface 60g (the pressure receiving portion Pr: see FIG. 8) of the cap 60. To do. Therefore, as shown in FIGS. 1 and 8, the cap 60 and the slide pin 54 again approach the opening 42b, and the front end surface 60d of the cap 60 is connected to the shoulder 42e of the stepped portion formed in the main body front end portion 42. Adhering to each other, a seal Sm (FIG. 8) is formed. Therefore, fluid leakage from the opening 42b is prevented.
Further, the back flow pressure of the resin in the resin supply passage 50 is also applied to the large-diameter base portion 52a of the sub slide pin 52 in the cylinder chamber 54b through the communication hole 54d, and the elastic force of the coil spring 58 is also added to the sub slide pin 52. The small diameter portion 52 b protrudes from the opening 60 a of the cap 60. A seal Ss (FIG. 8) that prevents leakage of fluid from the opening 42b and eliminates air in the opening 42b by being fitted in the opening 42b formed in the front end portion 42 without any gap. . Therefore, even if the molding machine nozzle 36 is separated from the nozzle touch surface 42a of the hot runner sprue 34 again, air does not enter from the opening 42b.

  The guide projection 40b of the intermediate body portion 40 and the communication hole 54d of the slide pin 54 have different circumferential installation intervals (the guide projection 40b is 90 ° apart and the communication hole 54d is 120 ° apart). ) Even if the slide pin 40 rotates in the resin supply path 50 and one communication hole 54d is blocked by the guide protrusion 40d, the other two communication holes 54d are not blocked by the guide protrusion 40d. Therefore, the back flow pressure of the resin in the resin supply path 50 is always applied to the large diameter base portion 52a of the sub slide pin 52 in the cylinder chamber 54b by the communication hole 54d.

According to the embodiment of the present invention configured as described above, the following operational effects can be obtained. According to the embodiment of the present invention, when the molding machine nozzle 36 is separated from the nozzle touch surface 42a of the hot runner sprue 36, the external pressurization to the resin in the resin supply path 50 is stopped. The member 66 receives the back flow pressure of the resin in the resin supply path 50 that exceeds atmospheric pressure, and the seal member 66 closes the opening 42 b of the resin supply path 50 from the inside of the resin supply path 50. Therefore, resin leakage from the hot runner sprue 34 is eliminated, and bubbles can be prevented from being mixed into the resin of the runner 30. In addition, since the opening 42b of the resin supply path 50 is blocked by the seal member 66 without causing a step with the nozzle touch surface 42a (FIGS. 1 and 8), the molding machine nozzle 34 once separated again becomes the hot runner sprue. No air is interposed between the molding machine nozzle 36 and the nozzle touch surface 42a when contacting the nozzle touch surface 42a. Therefore, air bubbles are not mixed into the runner 30 from between the molding machine nozzle 36 and the nozzle touch surface 42a.
When the resin is supplied from the molding machine nozzle 36, the seal member 66 receives the pressure of the resin supplied from the molding machine nozzle 36 and retreats from the opening 42 b of the resin supply path 50 into the resin supply path 50. The resin can be guided to the resin supply path 50 of the hot runner sprue 34. At this time, the seal member 66 is provided so as not to hinder the resin flow when the resin is supplied from the molding machine nozzle 36 (between the ribs 60e of the cap 60 and the main body middle portion 40). The resin flow part PA is provided between the guide protrusions 40b.), And the resin is smoothly filled into the product part of the mold.

  Here, the cap 60 constituting the main seal portion of the seal member 66 receives the back flow pressure of the resin in the resin supply passage 50 and the shoulder 42e of the step portion of the resin supply passage 50 from the manifold 12 side to the opening 42a side. , The opening 42b is closed from the inside of the resin supply path 50 without hindering the nozzle touch of the molding machine nozzle 36. Further, as described above, the sub seal portion 52 (sub slide pin) protruding from the main seal portions 54, 60 is fitted to the portion from the step portion 42c of the resin supply path 50 to the opening 42b without gap. The opening 42b of the resin supply path is closed without causing a step with the nozzle touch surface 42a.

  Further, the cap 60 constituting the main seal portion of the seal member 66 secures the resin flow when the resin is supplied from the molding machine nozzle 36 and the resin supply path when the resin supply from the molding machine nozzle 36 is stopped. 50 is provided with a pressure receiving portion Pr (FIG. 8) that receives the backflow pressure of the resin in the resin 50, the cap 60 constituting the main seal portion from the manifold 12 side with respect to the shoulder 42e of the step portion of the resin supply path 50. It is possible to abut against the opening 42b and prevent resin leakage. Further, since the resin flow at the time of supplying the resin from the molding machine nozzle 36 is not hindered, the injection molding is performed smoothly.

Further, when the resin is supplied from the molding machine nozzle 36, the resin flows in the space PA between the guide protrusion 40 b and the slide pin 54 that is slidably guided to the resin supply passage 50.
Further, the slide pin 54 constituting the main seal portion is slidably guided by the guide protrusion 40b, so that it receives the backflow pressure of the resin in the resin supply path when the resin supply from the molding machine nozzle 36 is stopped. The cap 60 constituting the main seal portion can abut against the shoulder 42e of the step portion of the resin supply path from the manifold 12 side toward the opening 42b side. Further, when the resin is supplied from the molding machine nozzle 36, the seal member 66 receives the pressure of the resin supplied from the molding machine nozzle 36 and retracts from the opening 42 b of the resin supply path 50 into the resin supply path 50. The resin can be smoothly guided to the resin supply path 50 of the hot runner sprue 34.

In addition, the main seal portions 54 and 60 (slide pins and caps) receive the back flow pressure of the resin in the resin supply path when the resin supply from the molding machine nozzle 36 is stopped, and are applied to the shoulder 42e of the step of the resin supply path. On the other hand, when abutting from the manifold 12 side toward the opening 42b side, the sub seal portion 52 (sub slide pin) also receives the back flow pressure of the resin through the resin flow distribution means 54d (communication hole). Then, the sub seal portion 52 protruding from the main seal portions 54 and 60 is fitted to the portion from the step portion 42c of the resin supply passage 50 to the opening 42b without any gap, so that the opening 42b of the resin supply passage 50 is a nozzle. The touch surface 42a is closed without causing a step.
On the other hand, when the resin is supplied from the molding machine nozzle 36, the sub seal portion 52 receives the resin supply pressure from the molding machine nozzle 36 and is immersed in the main seal portions 54 and 60, and the main seals 54 and 60 are also in the resin supply path. The resin flow into the resin resin supply path 50 is ensured by moving away from the shoulder 42e of the stepped portion 50 and retreating from the opening 42b of the resin supply path 50 into the resin supply path 50.

In the embodiment of the present invention, in order to simplify the structure, the main seal portions 54 and 60 are not provided with a rotation stopper, and the main seal portions 54 and 60 are formed on the inner wall of the resin supply path 50. The projection 40b is rotatably supported about the axis. However, since the guide projection 40b of the main body intermediate portion 40 and the communication hole 54d of the slide pin 54 have different circumferential installation intervals, it depends on the rotational phase of the main seal portion with respect to the resin supply path 50. Therefore, the guide protrusion 40b is not blocked. Therefore, regardless of the rotational phase of the main seal portion with respect to the resin supply passage 50, the sub seal portion 52 causes the reverse flow of the resin in the resin supply passage when the resin supply from the molding machine nozzle is stopped through the communication hole 54d. Under pressure, the main seal portions 54 and 60 protrude.
Note that the installation location of the communication hole 54d is not limited to the outer peripheral surface of the slide pin 54. For example, one or two or more holes communicating from the base end portion 54a of the slide pin 54 to the cylinder chamber 54b may be provided. good.

Further, the cylinder chamber 54b is provided with a spring 58 that urges the sub seal portion 52 in a direction in which the sub seal portion 52 protrudes from the main seal portions 54, 60, so that the sub seal portion 52 is supplied through the communication hole 54d. The main seal portions 54 and 60 are pushed out by the elastic force of the spring 58 together with the back flow pressure of the resin. Further, even when the internal pressure of the resin supply path 50 is reduced due to resin contraction caused by cooling the hot runner 30, the protruding state of the sub seal part 52 from the main seal parts 54 and 60 is maintained by the spring 58. Thus, it is possible to reliably prevent air from entering the hot runner 30.
In the embodiment of the present invention, a coil spring is used as the spring 58, but other elastic bodies may be used as necessary. Further, in the case where the problem of resin shrinkage due to cooling of the hot runner 30 does not occur, the spring 58 can be omitted.

In the above description, the operations of the main seal portions 54 and 60 and the sub seal portion 52 are performed simultaneously. However, in the embodiment of the present invention, the back flow pressure of the resin received by the main seal portions 54 and 60 is the back pressure of the resin received by the sub seal portion 52 (large diameter base portion 52a) in the cylinder chamber 54b and the elasticity of the spring 58. The pressure receiving area of the pressure receiving portion Pr (FIG. 8) of the main seal portions 54 and 60 and the opening area of the communication hole 54d may be determined so as to exceed the sum of the force.
In this case, when the resin supply from the molding machine nozzle 36 is stopped, the main seal portions 54 and 60 are initially shoulders of the shoulders of the resin supply passage 50 in response to the back flow pressure of the resin in the resin supply passage 50. It is possible to avoid resin leakage from the opening 42b by abutting against 42e. Subsequently, the sub seal portion 52 protrudes from the main seal portions 54 and 60 and fits into the portion from the step portion 42c of the resin supply passage 50 to the opening 42b without any gap, so that the opening of the resin supply passage 50 is a nozzle. It will be closed without causing a step difference from the touch surface.

Now, in FIG. 10 and FIG. 11, an application example (reference example) of the hot runner sprue 34 shown in FIG. 1 to FIG. In these application examples, the same or corresponding parts as those in the examples shown in FIGS.

  First, in the application example shown in FIG. 10, the slide pin 54 and the sub slide pin 52 are integrally configured in a state where the sub slide pin 52 constituting the sub seal protrudes from the tip of the slide pin 54 constituting the main seal portion. It is what has been. Accordingly, unlike the examples of FIGS. 1 to 9, all the structural portions that support the sub seal portion 52 so as to be able to protrude and retract with respect to the main seal portion 54 are unnecessary, and the cap 60 is also integrated with the slide pin 54. Further, a deep counterbore 42f having a diameter larger than that of the opening 42b and smaller than that of the enlarged diameter portion 42d is formed on the shoulder 42e of the step portion of the resin supply path 50. On the other hand, a projection 60j that projects along the counterbore 42f is formed on the surface of the cap 60 integral with the slide pin 54 that faces the shoulder 42e of the step portion of the resin supply path 50. The depth of the counterbore 42f and the height of the protrusion 60j are the same (h).

Therefore, in the state where the upper end surface 60d of the cap 60 is in contact with the shoulder 42e of the stepped portion of the resin supply path 50 and the seal Sm is formed to prevent fluid leakage from the opening 42b, The projection 60j is sealed without a gap. On the other hand, the resin supply path 50 has a stroke in which the seal member 66 formed integrally with the slide pin 54, the sub slide pin 52, and the cap 60 exceeds the depth of the counterbore 42f (the height of the annular protrusion 60j). (Indicated by a two-dot chain line in FIG. 10), the projection 60j comes off the counterbore 42f. Then, in a state where a part of the sub slide pin 52 is inserted in a portion from the step portion 42c to the opening 42b, the resin flow at the time of supplying the resin from the molding machine nozzle 36 is secured around the sub slide pin 52. An annular bypass for this purpose is formed by the counterbore 42f.
In the example of FIG. 10, the diameter of the cap 60 is constant, unlike the examples of FIGS. 1 to 9, in order to secure the area necessary for the seal Sm while providing the deep counterbore 42 f.

As described above, also in the example of FIG. 10, the cap 60 constituting the main seal portion of the seal member 66 receives the back flow pressure of the resin in the resin supply passage 50 to the shoulder 42 e of the step portion of the resin supply passage 50. By contacting, the opening 42b is closed from the inside of the resin supply path 50.
Further, the sub seal portion 52 protruding from the main seal portion 54 is fitted to the portion from the step portion 42c of the resin supply passage to the opening 42b without any gap, so that the opening 42b of the resin supply passage 50 is connected to the nozzle touch surface 42a. It will be closed without causing a step. In addition, as indicated by a two-dot chain line in the figure, in the state where a part of the sub seal portion 52 is inserted in a portion from the step portion 42c of the resin supply passage 50 to the opening 42b, an annular bypass 42f (depth counterbore). As a result, the flow of the resin is ensured, so that it is possible to prevent the length of the operation stroke required for the seal member 66 from being increased.

Further, since a projection 60j filling the annular bypass 42f is provided on the surface of the main seal portion 60 facing the shoulder 42e of the stepped portion of the resin supply path 50, following the bypass shape, the seal member When the main seal portion 54 of 66 receives the back pressure of the resin in the resin supply passage 50 and abuts against the shoulder 42e of the step portion of the resin supply passage 50, the main seal portion 54 contacts the shoulder 42e of the step portion of the resin supply passage 50. The protrusion 60j provided on the opposing surface fills the bypass 42f, and the possibility of air mixing into the resin can be eliminated.
Therefore, according to the example of FIG. 10, the seal member 66 is integrated with the slide pin 54, the sub-slide pin 52, and the cap 60, thereby simplifying the structure and similar to the example of FIGS. 1 to 9. It is possible to obtain the operational effects.

In the example shown in FIG. 11, the deep spot face 42f in FIG. 10 is replaced with a chamfer 42g, and the protrusion 60j in FIG. 10 is replaced with a truncated cone-shaped protrusion 60h following the shape of the chamfer 42g. It is. Also in this case, it is possible to obtain the same effect as the example of FIG. Further, the bypass is not necessarily annular, and one or a plurality of grooves divided in the circumferential direction may be provided.
Furthermore, if the lengthening of the operation stroke required for the seal member 66 is not considered as a problem, the deep spot face 42f and the protrusion 60j, the chamfer 42g and the protrusion 60h for forming the bypass can be omitted. In this case, when the seal member 66 is moved from the portion from the step portion 42e of the resin supply path 50 to the opening 42b until the sub seal portion 52 is completely extracted, the resin from the molding machine nozzle 36 is obtained. The resin flow at the time of supply is ensured.

Further, as shown in FIGS. 12 and 13, the deep spot face 42f and the protrusion 60j in FIG. 10 and the chamfer 42g and the protrusion 60h in FIG. 11 are omitted to sufficiently secure an area necessary for the seal Sm. Instead of the upper surface of the sub slide pin 52 fixed to the upper surface 60d of the cap 60 being a spherical concave surface 52c as in the examples of FIGS. 1 to 11, the protrusion height of the sub slide pin 52 is shown in FIG. As shown, the resin supply path 50 may be formed lower than the portion from the stepped portion 42c to the nozzle touch surface 42a.
In this case, there is a minute gap g between the nozzle touch surface 42a and the sub slide pin 52, that is, the sub slide pin 52 has a step difference from the nozzle touch surface 42a from the inside of the opening 42b. It does not close without occurring. However, the inventors have confirmed that no silver stripes are generated in the product even if air resulting from the minute gap g is mixed into the resin. Therefore, it can be adopted as a variation of the tip shape of the sub slide pin 52.

In addition, a conical protrusion 52 d is formed on the upper surface of the sub slide pin 52. As shown in FIG. 12 (a), the conical protrusion 52d has a height where the tip of the conical protrusion 52d does not protrude from the nozzle touch surface 42a in a state where the entire sub-slide pin 52 is inserted into the opening 42b. Thus, the molding machine nozzle 36 contacting the nozzle touch surface 42a is prevented from being blocked by the tip of the conical protrusion 52d. Then, the conical protrusion 52d can exhibit a rectifying effect of the resin supplied from the molding machine nozzle 36, and the resin fluidity in the resin supply path 50 can be enhanced. Furthermore, the resin fluidity in the resin supply path 50 is also improved by reducing the number of ribs 60e constituting the pressure receiving portion Pr (see FIG. 8) from four to three in FIG.
The sub-slide pins shown in FIGS. 12 and 13 can be applied to the examples shown in FIGS. 1 to 11 to obtain the same effects.

BRIEF DESCRIPTION OF THE DRAWINGS It is a hot runner sprue which concerns on embodiment of this invention, (a) is the top view, (b) is sectional drawing in the AA of (a), Comprising: The supply stop of the resin from a molding machine nozzle The state at the time is shown together with the manifold of the hot runner block. It is sectional drawing in the CC line of FIG.1 (b). It is sectional drawing in the DD line of FIG.1 (b). It is sectional drawing which shows the state at the time of supply of resin from the molding machine nozzle corresponding to (b) of FIG. It is a figure which shows the main body main body intermediate part of the hot runner sprue shown in FIG. 1, (a) is a top view, (b) is sectional drawing in the EE line of (a). It is a figure which shows the slide pin of the hot runner sprue shown in FIG. 1, (a) is a top view, (b) is the side view which showed a part in cross section. It is a figure which shows the cap of the hot runner sprue shown in FIG. 1, (a) is a top view, (b) is sectional drawing in the GG line of (a). It is a principal part enlarged view of FIG.1 (b). It is a principal part enlarged view of FIG. It is a principal part enlarged view of the application example (reference example) of the hot runner sprue which concerns on embodiment of this invention. It is a principal part enlarged view of the other application example of the hot runner sprue which concerns on embodiment of this invention. It is a principal part enlarged view of another application example of the hot runner sprue which concerns on embodiment of this invention, (a) is the state at the time of the supply stop of the resin from a molding machine nozzle, (b) is a molding machine. The state at the time of supply of resin from a nozzle is shown. It is the single figure of the slide pin of the hot runner sprue shown in FIG. 12, (a) is the top view, (b) is the side view. It is sectional drawing of the conventional injection mold provided with a hot runner. It is sectional drawing which shows the problem in the conventional hot runner.

  34: hot runner sprue, 36: molding machine nozzle, 38: main body base, 38a: hemispherical depression, 38b: communication hole, 40: intermediate part of main body, 40a: hole, 40b: guide protrusion, 40c: counterbore, 42: Main body tip, 42a: Nozzle touch surface, 42b: Opening, 42c: Stepped portion, 42d: Expanded diameter portion, 42e: Shoulder of stepped portion, 42f: Deep counterbore, 44: Main body, 50: Resin supply path, 52: Sub slide pin, 52a: Large diameter base, 52b: Small diameter portion, 52c: Spherical concave surface, 52d: Conical protrusion, 54: Slide pin, 54b: Cylinder chamber, 54d: Communication hole, 56: Stopper pin, 58: Coil spring, 60: cap, 60a: opening, 60c: stepped portion, 60d: distal end surface, 60e: rib, 60g: proximal end surface, 60j: protrusion, 66: seal member, 68: annular bypass

Claims (6)

A hot runner sprue that constitutes a connecting portion with the molding machine nozzle for feeding the resin supplied from the molding machine nozzle to the manifold of the hot runner block,
The main body of the hot runner sprue is formed with a nozzle touch surface with the nozzle of the molding machine and a resin supply path that opens to the nozzle touch surface and communicates with the manifold. A seal that blocks the opening from the inside of the resin supply path without disturbing the resin flow at the time of resin supply and receiving the back flow pressure of the resin in the resin supply path when the resin supply from the molding machine nozzle is stopped Members are provided,
In the resin supply path, a step portion that discontinuously increases the diameter is formed from the opening to the manifold, and the seal member has a shoulder of the step portion of the resin supply path, A main seal portion having a close contact surface abutting from the manifold side toward the opening side, and a fitting that protrudes from the main seal portion and fits into a portion extending from the step portion of the resin supply path to the opening without any gap A secondary seal portion having a surface,
The main seal portion of the seal member receives pressure to receive the back flow pressure of the resin in the resin supply path when the resin supply from the molding machine nozzle is stopped while ensuring the resin flow when the resin is supplied from the molding machine nozzle. Part is provided,
The sub-seal portion is configured to close the opening from the inner side of the resin supply path without causing a step with the nozzle touch surface, or the protruding height is from the step portion of the resin supply path. It is formed lower than the part that reaches the nozzle touch surface, and is held by the main seal part so as to be able to protrude and retract with respect to the main seal part,
Further, the main seal portion is provided with a reverse flow pressure of the resin in the resin supply passage when the supply of resin from the molding machine nozzle is stopped to cause the sub seal portion to protrude from the main seal portion. A hot runner sprue characterized by being provided with resin flow dividing means . A plurality of guide protrusions extending in the resin flow direction are formed on the inner wall of the resin supply path, and the main seal portion of the seal member is configured by a slide pin that is slidably guided by the guide protrusion. The hot runner sprue according to claim 1, wherein The sub seal part is configured such that a part of a sub slide pin that is slidably guided in a cylinder chamber formed in the main seal part is configured to be able to protrude and retract from a tip of the main seal part. The hot runner sprue according to claim 1 or 2 , wherein a communication hole that communicates the cylinder chamber and the resin supply path is provided in the section as the resin diverting means. The main seal is rotatably supported around the axis by a guide protrusion formed on the inner wall of the resin supply path, and the guide protrusion is blocked regardless of the rotational phase with respect to the resin supply path. 4. The hot runner sprue according to claim 3 , wherein one or more of the communication holes are provided at a position where they are not damaged. The hot runner sprue according to claim 3 or 4 , wherein the cylinder chamber is provided with a spring that biases the sub seal portion in a direction in which the sub seal portion protrudes from the main seal portion. The pressure receiving area of the pressure receiving portion of the main seal portion so that the back flow pressure of the resin received by the main seal portion exceeds the sum of the back flow pressure of the resin received by the sub seal portion and the elastic force of the spring in the cylinder chamber. The hot runner sprue according to claim 5 , wherein an opening area of the communication hole is determined.

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